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[原]零基础学习视频解码之解码声音
关于视频解码以及使用SDL显示详情见：[原]零基础学习视频解码之解码图像
SDL播放声音的方式是这样的：
你建立你的音频选项：采样率（在SDL中称为"频率"），通道数，等等，我们还应该设置一个回调函数和用户数据。当我们开始播放音频，SDL会不断的回调这个函数，让它充满一定数量字节的音频缓冲区，然后我们把这些信息放到SDL_AudioSpec数据结构中，我们接着调用SDL_OpenAudio，这将打开音频设备，还给我们一个AudioSpec结构。
freq：采样率
format：我们将给SDL什么样的格式
channels：音频通道
silence：音频缓冲区默认值，通常为0
samples：当SDL向我们请求更多的音频缓冲区的大小的时候设置的
callback：回调函数
userdata：SDL会给我们的回调void指针的用户数据，我们必须让它知道我们的编解码器上下文
现在我们开始获取流音频信息，但我们怎么处理这些信息？解决的办法是要创造一种数据结构，我们可以在audio_callback得到音频数据然后保存获取到的数据包！所以我们要做的是创建一个队列的数据包。ffmpeg甚至还带有一个结构来帮助我们做这：AVPacketList，这仅仅是一个链表的数据包，我们还需要自己维护接受到的数据包队列。
首先还是配置Eclipse相关依赖库的环境：
Project->Properties->C/C++ General->Path and Symbols->Libraries->Add->SDL、avcode、avutil、avformat、swscale
一、定义一个数据结构用来保存AVPacketList队列
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int main(int argc, char* args[]) { return EXIT_SUCCESS;}
二、初始化这个数据队列：
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int main(int argc, char* args[]) { return EXIT_SUCCESS;}
你会注意到，我们有一个互斥体和条件变量。这是因为SDL用一个单独的线程运行音频处理。如果我们不把排好队，我们真的会毁了我们的数据。接下来我们将看到如何在队列的实现。
三、添加一个AVPacket到队列中
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}int main(int argc, char* args[]) { return EXIT_SUCCESS;}
四、从队列中获取一个AVPacket
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int main(int argc, char* args[]) { return EXIT_SUCCESS;}
五、解码音频
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data =http://www.mamicode.com/ NULL; static int audio_pkt_size = 0; static AVFrame frame; int len1, data_size = 0; for (;;) { while (audio_pkt_size > 0) { int got_frame = 0; len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt); if (len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if (got_frame) { data_size = frame.linesize[0]; /* data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame.nb_samples, aCodecCtx->sample_fmt, 1); */ memcpy(audio_buf, frame.data[0], data_size); } if (data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if (pkt.data) av_free_packet(&pkt); if (quit) { return -1; } if (packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } return 0;}int main(int argc, char* args[]) { return EXIT_SUCCESS;}
六、处理call_back
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data =http://www.mamicode.com/ NULL; static int audio_pkt_size = 0; static AVFrame frame; int len1, data_size = 0; for (;;) { while (audio_pkt_size > 0) { int got_frame = 0; len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt); if (len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if (got_frame) { data_size = frame.linesize[0]; /* data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame.nb_samples, aCodecCtx->sample_fmt, 1); */ memcpy(audio_buf, frame.data[0], data_size); } if (data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if (pkt.data) av_free_packet(&pkt); if (quit) { return -1; } if (packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } return 0;}void audio_callback(void *userdata, Uint8 *stream, int len) { AVCodecContext *aCodecCtx = (AVCodecContext *) userdata; int len1, audio_size; static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; static unsigned int audio_buf_size = 0; static unsigned int audio_buf_index = 0; while (len > 0) { if (audio_buf_index >= audio_buf_size) { /* We have already sent all our data; get more */ audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf)); if (audio_size < 0) { /* If error, output silence */ audio_buf_size = 1024; // arbitrary? memset(audio_buf, 0, audio_buf_size); } else { audio_buf_size = audio_size; } audio_buf_index = 0; } len1 = audio_buf_size - audio_buf_index; if (len1 > len) len1 = len; memcpy(stream, (uint8_t *) audio_buf + audio_buf_index, len1); len -= len1; stream += len1; audio_buf_index += len1; }}int main(int argc, char* args[]) { return EXIT_SUCCESS;}
七、初始化音频相关的变量
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data =http://www.mamicode.com/ NULL; static int audio_pkt_size = 0; static AVFrame frame; int len1, data_size = 0; for (;;) { while (audio_pkt_size > 0) { int got_frame = 0; len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt); if (len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if (got_frame) { data_size = frame.linesize[0]; /* data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame.nb_samples, aCodecCtx->sample_fmt, 1); */ memcpy(audio_buf, frame.data[0], data_size); } if (data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if (pkt.data) av_free_packet(&pkt); if (quit) { return -1; } if (packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } return 0;}void audio_callback(void *userdata, Uint8 *stream, int len) { AVCodecContext *aCodecCtx = (AVCodecContext *) userdata; int len1, audio_size; static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; static unsigned int audio_buf_size = 0; static unsigned int audio_buf_index = 0; while (len > 0) { if (audio_buf_index >= audio_buf_size) { /* We have already sent all our data; get more */ audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf)); if (audio_size < 0) { /* If error, output silence */ audio_buf_size = 1024; // arbitrary? memset(audio_buf, 0, audio_buf_size); } else { audio_buf_size = audio_size; } audio_buf_index = 0; } len1 = audio_buf_size - audio_buf_index; if (len1 > len) len1 = len; memcpy(stream, (uint8_t *) audio_buf + audio_buf_index, len1); len -= len1; stream += len1; audio_buf_index += len1; }}int main(int argc, char* args[]) { AVFormatContext *pFormatCtx = NULL; int i, videoStream, audioStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVPacket packet; struct SwsContext * pSwsCtx; int frameFinished; AVCodecContext *aCodecCtx; AVCodec *aCodec; SDL_Overlay *bmp; SDL_Surface *screen; SDL_Rect rect; SDL_Event event; SDL_AudioSpec wanted_spec, spec; return EXIT_SUCCESS;}
八、注册初始化与打开视频相关函数
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data =http://www.mamicode.com/ NULL; static int audio_pkt_size = 0; static AVFrame frame; int len1, data_size = 0; for (;;) { while (audio_pkt_size > 0) { int got_frame = 0; len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt); if (len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if (got_frame) { data_size = frame.linesize[0]; /* data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame.nb_samples, aCodecCtx->sample_fmt, 1); */ memcpy(audio_buf, frame.data[0], data_size); } if (data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if (pkt.data) av_free_packet(&pkt); if (quit) { return -1; } if (packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } return 0;}void audio_callback(void *userdata, Uint8 *stream, int len) { AVCodecContext *aCodecCtx = (AVCodecContext *) userdata; int len1, audio_size; static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; static unsigned int audio_buf_size = 0; static unsigned int audio_buf_index = 0; while (len > 0) { if (audio_buf_index >= audio_buf_size) { /* We have already sent all our data; get more */ audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf)); if (audio_size < 0) { /* If error, output silence */ audio_buf_size = 1024; // arbitrary? memset(audio_buf, 0, audio_buf_size); } else { audio_buf_size = audio_size; } audio_buf_index = 0; } len1 = audio_buf_size - audio_buf_index; if (len1 > len) len1 = len; memcpy(stream, (uint8_t *) audio_buf + audio_buf_index, len1); len -= len1; stream += len1; audio_buf_index += len1; }}int main(int argc, char* args[]) { AVFormatContext *pFormatCtx = NULL; int i, videoStream, audioStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVPacket packet; struct SwsContext * pSwsCtx; int frameFinished; AVCodecContext *aCodecCtx; AVCodec *aCodec; SDL_Overlay *bmp; SDL_Surface *screen; SDL_Rect rect; SDL_Event event; SDL_AudioSpec wanted_spec, spec; char filePath[] = "./src/a.mp4"; // Register all formats and codecs av_register_all(); if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) { fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError()); exit(1); } // Open video file if (avformat_open_input(&pFormatCtx, filePath, NULL, NULL) != 0) return -1; // Couldn‘t open file // Retrieve stream information if (avformat_find_stream_info(pFormatCtx, NULL) < 0) return -1; // Couldn‘t find stream information // Dump information about file onto standard error av_dump_format(pFormatCtx, 0, filePath, 0); return EXIT_SUCCESS;}
九、找到第一条视频流和音频流
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data =http://www.mamicode.com/ NULL; static int audio_pkt_size = 0; static AVFrame frame; int len1, data_size = 0; for (;;) { while (audio_pkt_size > 0) { int got_frame = 0; len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt); if (len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if (got_frame) { data_size = frame.linesize[0]; /* data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame.nb_samples, aCodecCtx->sample_fmt, 1); */ memcpy(audio_buf, frame.data[0], data_size); } if (data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if (pkt.data) av_free_packet(&pkt); if (quit) { return -1; } if (packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } return 0;}void audio_callback(void *userdata, Uint8 *stream, int len) { AVCodecContext *aCodecCtx = (AVCodecContext *) userdata; int len1, audio_size; static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; static unsigned int audio_buf_size = 0; static unsigned int audio_buf_index = 0; while (len > 0) { if (audio_buf_index >= audio_buf_size) { /* We have already sent all our data; get more */ audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf)); if (audio_size < 0) { /* If error, output silence */ audio_buf_size = 1024; // arbitrary? memset(audio_buf, 0, audio_buf_size); } else { audio_buf_size = audio_size; } audio_buf_index = 0; } len1 = audio_buf_size - audio_buf_index; if (len1 > len) len1 = len; memcpy(stream, (uint8_t *) audio_buf + audio_buf_index, len1); len -= len1; stream += len1; audio_buf_index += len1; }}int main(int argc, char* args[]) { AVFormatContext *pFormatCtx = NULL; int i, videoStream, audioStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVPacket packet; struct SwsContext * pSwsCtx; int frameFinished; AVCodecContext *aCodecCtx; AVCodec *aCodec; SDL_Overlay *bmp; SDL_Surface *screen; SDL_Rect rect; SDL_Event event; SDL_AudioSpec wanted_spec, spec; char filePath[] = "./src/a.mp4"; // Register all formats and codecs av_register_all(); if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) { fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError()); exit(1); } // Open video file if (avformat_open_input(&pFormatCtx, filePath, NULL, NULL) != 0) return -1; // Couldn‘t open file // Retrieve stream information if (avformat_find_stream_info(pFormatCtx, NULL) < 0) return -1; // Couldn‘t find stream information // Dump information about file onto standard error av_dump_format(pFormatCtx, 0, filePath, 0); // Find the first video stream videoStream = -1; audioStream = -1; for (i = 0; i < pFormatCtx->nb_streams; i++) { if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO && videoStream < 0) { videoStream = i; } if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO && audioStream < 0) { audioStream = i; } } if (videoStream == -1) return -1; // Didn‘t find a video stream if (audioStream == -1) return -1; return EXIT_SUCCESS;}
十、注册音频相关设置到SDL_AudioSpec中
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data =http://www.mamicode.com/ NULL; static int audio_pkt_size = 0; static AVFrame frame; int len1, data_size = 0; for (;;) { while (audio_pkt_size > 0) { int got_frame = 0; len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt); if (len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if (got_frame) { data_size = frame.linesize[0]; /* data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame.nb_samples, aCodecCtx->sample_fmt, 1); */ memcpy(audio_buf, frame.data[0], data_size); } if (data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if (pkt.data) av_free_packet(&pkt); if (quit) { return -1; } if (packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } return 0;}void audio_callback(void *userdata, Uint8 *stream, int len) { AVCodecContext *aCodecCtx = (AVCodecContext *) userdata; int len1, audio_size; static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; static unsigned int audio_buf_size = 0; static unsigned int audio_buf_index = 0; while (len > 0) { if (audio_buf_index >= audio_buf_size) { /* We have already sent all our data; get more */ audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf)); if (audio_size < 0) { /* If error, output silence */ audio_buf_size = 1024; // arbitrary? memset(audio_buf, 0, audio_buf_size); } else { audio_buf_size = audio_size; } audio_buf_index = 0; } len1 = audio_buf_size - audio_buf_index; if (len1 > len) len1 = len; memcpy(stream, (uint8_t *) audio_buf + audio_buf_index, len1); len -= len1; stream += len1; audio_buf_index += len1; }}int main(int argc, char* args[]) { AVFormatContext *pFormatCtx = NULL; int i, videoStream, audioStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVPacket packet; struct SwsContext * pSwsCtx; int frameFinished; AVCodecContext *aCodecCtx; AVCodec *aCodec; SDL_Overlay *bmp; SDL_Surface *screen; SDL_Rect rect; SDL_Event event; SDL_AudioSpec wanted_spec, spec; char filePath[] = "./src/a.mp4"; // Register all formats and codecs av_register_all(); if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) { fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError()); exit(1); } // Open video file if (avformat_open_input(&pFormatCtx, filePath, NULL, NULL) != 0) return -1; // Couldn‘t open file // Retrieve stream information if (avformat_find_stream_info(pFormatCtx, NULL) < 0) return -1; // Couldn‘t find stream information // Dump information about file onto standard error av_dump_format(pFormatCtx, 0, filePath, 0); // Find the first video stream videoStream = -1; audioStream = -1; for (i = 0; i < pFormatCtx->nb_streams; i++) { if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO && videoStream < 0) { videoStream = i; } if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO && audioStream < 0) { audioStream = i; } } if (videoStream == -1) return -1; // Didn‘t find a video stream if (audioStream == -1) return -1; aCodecCtx = pFormatCtx->streams[audioStream]->codec; // Set audio settings from codec info wanted_spec.freq = aCodecCtx->sample_rate; wanted_spec.format = AUDIO_S16SYS; wanted_spec.channels = aCodecCtx->channels; wanted_spec.silence = 0; wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE; wanted_spec.callback = audio_callback; wanted_spec.userdata = aCodecCtx; return EXIT_SUCCESS;}
十一、初始化音频数据队列并打开音频设备
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data =http://www.mamicode.com/ NULL; static int audio_pkt_size = 0; static AVFrame frame; int len1, data_size = 0; for (;;) { while (audio_pkt_size > 0) { int got_frame = 0; len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt); if (len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if (got_frame) { data_size = frame.linesize[0]; /* data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame.nb_samples, aCodecCtx->sample_fmt, 1); */ memcpy(audio_buf, frame.data[0], data_size); } if (data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if (pkt.data) av_free_packet(&pkt); if (quit) { return -1; } if (packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } return 0;}void audio_callback(void *userdata, Uint8 *stream, int len) { AVCodecContext *aCodecCtx = (AVCodecContext *) userdata; int len1, audio_size; static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; static unsigned int audio_buf_size = 0; static unsigned int audio_buf_index = 0; while (len > 0) { if (audio_buf_index >= audio_buf_size) { /* We have already sent all our data; get more */ audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf)); if (audio_size < 0) { /* If error, output silence */ audio_buf_size = 1024; // arbitrary? memset(audio_buf, 0, audio_buf_size); } else { audio_buf_size = audio_size; } audio_buf_index = 0; } len1 = audio_buf_size - audio_buf_index; if (len1 > len) len1 = len; memcpy(stream, (uint8_t *) audio_buf + audio_buf_index, len1); len -= len1; stream += len1; audio_buf_index += len1; }}int main(int argc, char* args[]) { AVFormatContext *pFormatCtx = NULL; int i, videoStream, audioStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVPacket packet; struct SwsContext * pSwsCtx; int frameFinished; AVCodecContext *aCodecCtx; AVCodec *aCodec; SDL_Overlay *bmp; SDL_Surface *screen; SDL_Rect rect; SDL_Event event; SDL_AudioSpec wanted_spec, spec; char filePath[] = "./src/a.mp4"; // Register all formats and codecs av_register_all(); if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) { fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError()); exit(1); } // Open video file if (avformat_open_input(&pFormatCtx, filePath, NULL, NULL) != 0) return -1; // Couldn‘t open file // Retrieve stream information if (avformat_find_stream_info(pFormatCtx, NULL) < 0) return -1; // Couldn‘t find stream information // Dump information about file onto standard error av_dump_format(pFormatCtx, 0, filePath, 0); // Find the first video stream videoStream = -1; audioStream = -1; for (i = 0; i < pFormatCtx->nb_streams; i++) { if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO && videoStream < 0) { videoStream = i; } if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO && audioStream < 0) { audioStream = i; } } if (videoStream == -1) return -1; // Didn‘t find a video stream if (audioStream == -1) return -1; aCodecCtx = pFormatCtx->streams[audioStream]->codec; // Set audio settings from codec info wanted_spec.freq = aCodecCtx->sample_rate; wanted_spec.format = AUDIO_S16SYS; wanted_spec.channels = aCodecCtx->channels; wanted_spec.silence = 0; wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE; wanted_spec.callback = audio_callback; wanted_spec.userdata = aCodecCtx; if (SDL_OpenAudio(&wanted_spec, &spec) < 0) { fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError()); return -1; } aCodec = avcodec_find_decoder(aCodecCtx->codec_id); if (!aCodec) { fprintf(stderr, "Unsupported codec!\n"); return -1; } avcodec_open2(aCodecCtx, aCodec, NULL); // audio_st = pFormatCtx->streams[index] packet_queue_init(&audioq); SDL_PauseAudio(0); return EXIT_SUCCESS;}
十二、初始化与Video相关的环境变量
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data =http://www.mamicode.com/ NULL; static int audio_pkt_size = 0; static AVFrame frame; int len1, data_size = 0; for (;;) { while (audio_pkt_size > 0) { int got_frame = 0; len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt); if (len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if (got_frame) { data_size = frame.linesize[0]; /* data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame.nb_samples, aCodecCtx->sample_fmt, 1); */ memcpy(audio_buf, frame.data[0], data_size); } if (data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if (pkt.data) av_free_packet(&pkt); if (quit) { return -1; } if (packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } return 0;}void audio_callback(void *userdata, Uint8 *stream, int len) { AVCodecContext *aCodecCtx = (AVCodecContext *) userdata; int len1, audio_size; static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; static unsigned int audio_buf_size = 0; static unsigned int audio_buf_index = 0; while (len > 0) { if (audio_buf_index >= audio_buf_size) { /* We have already sent all our data; get more */ audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf)); if (audio_size < 0) { /* If error, output silence */ audio_buf_size = 1024; // arbitrary? memset(audio_buf, 0, audio_buf_size); } else { audio_buf_size = audio_size; } audio_buf_index = 0; } len1 = audio_buf_size - audio_buf_index; if (len1 > len) len1 = len; memcpy(stream, (uint8_t *) audio_buf + audio_buf_index, len1); len -= len1; stream += len1; audio_buf_index += len1; }}int main(int argc, char* args[]) { AVFormatContext *pFormatCtx = NULL; int i, videoStream, audioStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVPacket packet; struct SwsContext * pSwsCtx; int frameFinished; AVCodecContext *aCodecCtx; AVCodec *aCodec; SDL_Overlay *bmp; SDL_Surface *screen; SDL_Rect rect; SDL_Event event; SDL_AudioSpec wanted_spec, spec; char filePath[] = "./src/a.mp4"; // Register all formats and codecs av_register_all(); if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) { fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError()); exit(1); } // Open video file if (avformat_open_input(&pFormatCtx, filePath, NULL, NULL) != 0) return -1; // Couldn‘t open file // Retrieve stream information if (avformat_find_stream_info(pFormatCtx, NULL) < 0) return -1; // Couldn‘t find stream information // Dump information about file onto standard error av_dump_format(pFormatCtx, 0, filePath, 0); // Find the first video stream videoStream = -1; audioStream = -1; for (i = 0; i < pFormatCtx->nb_streams; i++) { if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO && videoStream < 0) { videoStream = i; } if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO && audioStream < 0) { audioStream = i; } } if (videoStream == -1) return -1; // Didn‘t find a video stream if (audioStream == -1) return -1; aCodecCtx = pFormatCtx->streams[audioStream]->codec; // Set audio settings from codec info wanted_spec.freq = aCodecCtx->sample_rate; wanted_spec.format = AUDIO_S16SYS; wanted_spec.channels = aCodecCtx->channels; wanted_spec.silence = 0; wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE; wanted_spec.callback = audio_callback; wanted_spec.userdata = aCodecCtx; if (SDL_OpenAudio(&wanted_spec, &spec) < 0) { fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError()); return -1; } aCodec = avcodec_find_decoder(aCodecCtx->codec_id); if (!aCodec) { fprintf(stderr, "Unsupported codec!\n"); return -1; } avcodec_open2(aCodecCtx, aCodec, NULL); // audio_st = pFormatCtx->streams[index] packet_queue_init(&audioq); SDL_PauseAudio(0); // Get a pointer to the codec context for the video stream pCodecCtx = pFormatCtx->streams[videoStream]->codec; // Find the decoder for the video stream pCodec = avcodec_find_decoder(pCodecCtx->codec_id); if (pCodec == NULL) { fprintf(stderr, "Unsupported codec!\n"); return -1; // Codec not found } // Open codec if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0) return -1; // Could not open codec // Allocate video frame pFrame = avcodec_alloc_frame(); pSwsCtx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_FAST_BILINEAR, NULL, NULL, NULL); return EXIT_SUCCESS;}
十三、初始化视频输出环境
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data =http://www.mamicode.com/ NULL; static int audio_pkt_size = 0; static AVFrame frame; int len1, data_size = 0; for (;;) { while (audio_pkt_size > 0) { int got_frame = 0; len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt); if (len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if (got_frame) { data_size = frame.linesize[0]; /* data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame.nb_samples, aCodecCtx->sample_fmt, 1); */ memcpy(audio_buf, frame.data[0], data_size); } if (data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if (pkt.data) av_free_packet(&pkt); if (quit) { return -1; } if (packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } return 0;}void audio_callback(void *userdata, Uint8 *stream, int len) { AVCodecContext *aCodecCtx = (AVCodecContext *) userdata; int len1, audio_size; static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; static unsigned int audio_buf_size = 0; static unsigned int audio_buf_index = 0; while (len > 0) { if (audio_buf_index >= audio_buf_size) { /* We have already sent all our data; get more */ audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf)); if (audio_size < 0) { /* If error, output silence */ audio_buf_size = 1024; // arbitrary? memset(audio_buf, 0, audio_buf_size); } else { audio_buf_size = audio_size; } audio_buf_index = 0; } len1 = audio_buf_size - audio_buf_index; if (len1 > len) len1 = len; memcpy(stream, (uint8_t *) audio_buf + audio_buf_index, len1); len -= len1; stream += len1; audio_buf_index += len1; }}int main(int argc, char* args[]) { AVFormatContext *pFormatCtx = NULL; int i, videoStream, audioStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVPacket packet; struct SwsContext * pSwsCtx; int frameFinished; AVCodecContext *aCodecCtx; AVCodec *aCodec; SDL_Overlay *bmp; SDL_Surface *screen; SDL_Rect rect; SDL_Event event; SDL_AudioSpec wanted_spec, spec; char filePath[] = "./src/a.mp4"; // Register all formats and codecs av_register_all(); if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) { fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError()); exit(1); } // Open video file if (avformat_open_input(&pFormatCtx, filePath, NULL, NULL) != 0) return -1; // Couldn‘t open file // Retrieve stream information if (avformat_find_stream_info(pFormatCtx, NULL) < 0) return -1; // Couldn‘t find stream information // Dump information about file onto standard error av_dump_format(pFormatCtx, 0, filePath, 0); // Find the first video stream videoStream = -1; audioStream = -1; for (i = 0; i < pFormatCtx->nb_streams; i++) { if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO && videoStream < 0) { videoStream = i; } if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO && audioStream < 0) { audioStream = i; } } if (videoStream == -1) return -1; // Didn‘t find a video stream if (audioStream == -1) return -1; aCodecCtx = pFormatCtx->streams[audioStream]->codec; // Set audio settings from codec info wanted_spec.freq = aCodecCtx->sample_rate; wanted_spec.format = AUDIO_S16SYS; wanted_spec.channels = aCodecCtx->channels; wanted_spec.silence = 0; wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE; wanted_spec.callback = audio_callback; wanted_spec.userdata = aCodecCtx; if (SDL_OpenAudio(&wanted_spec, &spec) < 0) { fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError()); return -1; } aCodec = avcodec_find_decoder(aCodecCtx->codec_id); if (!aCodec) { fprintf(stderr, "Unsupported codec!\n"); return -1; } avcodec_open2(aCodecCtx, aCodec, NULL); // audio_st = pFormatCtx->streams[index] packet_queue_init(&audioq); SDL_PauseAudio(0); // Get a pointer to the codec context for the video stream pCodecCtx = pFormatCtx->streams[videoStream]->codec; // Find the decoder for the video stream pCodec = avcodec_find_decoder(pCodecCtx->codec_id); if (pCodec == NULL) { fprintf(stderr, "Unsupported codec!\n"); return -1; // Codec not found } // Open codec if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0) return -1; // Could not open codec // Allocate video frame pFrame = avcodec_alloc_frame(); pSwsCtx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_FAST_BILINEAR, NULL, NULL, NULL); // Make a screen to put our video#ifndef __DARWIN__ screen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 0, 0);#else screen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 24, 0);#endif if (!screen) { fprintf(stderr, "SDL: could not set video mode - exiting\n"); exit(1); } // Allocate a place to put our YUV image on that screen bmp = SDL_CreateYUVOverlay(pCodecCtx->width, pCodecCtx->height, SDL_YV12_OVERLAY, screen); return EXIT_SUCCESS;}
十四、循环读包，并根据是音频包还是视频包，做相应处理
/* ============================================================================ Name : VideoDecodeTutorial2_1.c Author : clarck Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style ============================================================================ */#include <stdio.h>#include <stdlib.h>#include "SDL/SDL.h"#include "SDL/SDL_thread.h"#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libavutil/pixfmt.h"#include "libswscale/swscale.h"#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#define SDL_AUDIO_BUFFER_SIZE 1024#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audiotypedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond;} PacketQueue;PacketQueue audioq;int quit = 0;void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond();}int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if (av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0;}static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for (;;) { if (quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret;}int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data =http://www.mamicode.com/ NULL; static int audio_pkt_size = 0; static AVFrame frame; int len1, data_size = 0; for (;;) { while (audio_pkt_size > 0) { int got_frame = 0; len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt); if (len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if (got_frame) { data_size = frame.linesize[0]; /* data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame.nb_samples, aCodecCtx->sample_fmt, 1); */ memcpy(audio_buf, frame.data[0], data_size); } if (data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if (pkt.data) av_free_packet(&pkt); if (quit) { return -1; } if (packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } return 0;}void audio_callback(void *userdata, Uint8 *stream, int len) { AVCodecContext *aCodecCtx = (AVCodecContext *) userdata; int len1, audio_size; static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; static unsigned int audio_buf_size = 0; static unsigned int audio_buf_index = 0; while (len > 0) { if (audio_buf_index >= audio_buf_size) { /* We have already sent all our data; get more */ audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf)); if (audio_size < 0) { /* If error, output silence */ audio_buf_size = 1024; // arbitrary? memset(audio_buf, 0, audio_buf_size); } else { audio_buf_size = audio_size; } audio_buf_index = 0; } len1 = audio_buf_size - audio_buf_index; if (len1 > len) len1 = len; memcpy(stream, (uint8_t *) audio_buf + audio_buf_index, len1); len -= len1; stream += len1; audio_buf_index += len1; }}int main(int argc, char* args[]) { AVFormatContext *pFormatCtx = NULL; int i, videoStream, audioStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVPacket packet; struct SwsContext * pSwsCtx; int frameFinished; AVCodecContext *aCodecCtx; AVCodec *aCodec; SDL_Overlay *bmp; SDL_Surface *screen; SDL_Rect rect; SDL_Event event; SDL_AudioSpec wanted_spec, spec; char filePath[] = "./src/a.mp4"; // Register all formats and codecs av_register_all(); if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) { fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError()); exit(1); } // Open video file if (avformat_open_input(&pFormatCtx, filePath, NULL, NULL) != 0) return -1; // Couldn‘t open file // Retrieve stream information if (avformat_find_stream_info(pFormatCtx, NULL) < 0) return -1; // Couldn‘t find stream information // Dump information about file onto standard error av_dump_format(pFormatCtx, 0, filePath, 0); // Find the first video stream videoStream = -1; audioStream = -1; for (i = 0; i < pFormatCtx->nb_streams; i++) { if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO && videoStream < 0) { videoStream = i; } if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO && audioStream < 0) { audioStream = i; } } if (videoStream == -1) return -1; // Didn‘t find a video stream if (audioStream == -1) return -1; aCodecCtx = pFormatCtx->streams[audioStream]->codec; // Set audio settings from codec info wanted_spec.freq = aCodecCtx->sample_rate; wanted_spec.format = AUDIO_S16SYS; wanted_spec.channels = aCodecCtx->channels; wanted_spec.silence = 0; wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE; wanted_spec.callback = audio_callback; wanted_spec.userdata = aCodecCtx; if (SDL_OpenAudio(&wanted_spec, &spec) < 0) { fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError()); return -1; } aCodec = avcodec_find_decoder(aCodecCtx->codec_id); if (!aCodec) { fprintf(stderr, "Unsupported codec!\n"); return -1; } avcodec_open2(aCodecCtx, aCodec, NULL); // audio_st = pFormatCtx->streams[index] packet_queue_init(&audioq); SDL_PauseAudio(0); // Get a pointer to the codec context for the video stream pCodecCtx = pFormatCtx->streams[videoStream]->codec; // Find the decoder for the video stream pCodec = avcodec_find_decoder(pCodecCtx->codec_id); if (pCodec == NULL) { fprintf(stderr, "Unsupported codec!\n"); return -1; // Codec not found } // Open codec if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0) return -1; // Could not open codec // Allocate video frame pFrame = avcodec_alloc_frame(); pSwsCtx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_FAST_BILINEAR, NULL, NULL, NULL); // Make a screen to put our video#ifndef __DARWIN__ screen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 0, 0);#else screen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 24, 0);#endif if (!screen) { fprintf(stderr, "SDL: could not set video mode - exiting\n"); exit(1); } // Allocate a place to put our YUV image on that screen bmp = SDL_CreateYUVOverlay(pCodecCtx->width, pCodecCtx->height, SDL_YV12_OVERLAY, screen); // Read frames and save first five frames to disk i = 0; while (av_read_frame(pFormatCtx, &packet) >= 0) { // Is this a packet from the video stream? if (packet.stream_index == videoStream) { // Decode video frame avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet); // Did we get a video frame? if (frameFinished) { SDL_LockYUVOverlay(bmp); AVPicture pict; pict.data[0] = bmp->pixels[0]; pict.data[1] = bmp->pixels[2]; pict.data[2] = bmp->pixels[1]; pict.linesize[0] = bmp->pitches[0]; pict.linesize[1] = bmp->pitches[2]; pict.linesize[2] = bmp->pitches[1]; // Convert the image into YUV format that SDL uses sws_scale(pSwsCtx, (const uint8_t * const *) pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pict.data, pict.linesize); SDL_UnlockYUVOverlay(bmp); rect.x = 0; rect.y = 0; rect.w = pCodecCtx->width; rect.h = pCodecCtx->height; SDL_DisplayYUVOverlay(bmp, &rect); av_free_packet(&packet); } } else if (packet.stream_index == audioStream) { packet_queue_put(&audioq, &packet); } else { av_free_packet(&packet); } // Free the packet that was allocated by av_read_frame SDL_PollEvent(&event); switch (event.type) { case SDL_QUIT: quit = 1; SDL_Quit(); exit(0); break; default: break; } } // Free the YUV frame av_free(pFrame); // Close the codec avcodec_close(pCodecCtx); // Close the video file avformat_close_input(&pFormatCtx); return EXIT_SUCCESS;}
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