首页 > 代码库 > Android中播放DSD音乐
Android中播放DSD音乐
Github上有个简单的Alsa DSD测试程序，可以播放DSD，地址位于：https://github.com/zonque/alsa-dsd-player 细看其代码，发现有ALSA_FORMAT_SND_PCM_FORMAT_DSD_U8的定义，详情如下：
#if 1/* 8-bit DSD */#define ALSA_FORMAT SND_PCM_FORMAT_DSD_U8#define SAMPLE_SIZE (sizeof(uint8_t) * 2)#define SAMPLE_RATE_DIV 1#else/* 16-bit DSD */#define ALSA_FORMAT SND_PCM_FORMAT_DSD_U16#define SAMPLE_SIZE (sizeof(uint16_t) * 2)#define SAMPLE_RATE_DIV 2#endif
那么在Android中能运行这个测试程序吗？ALSA_FORMAT_SND_PCM_FORMAT_DSD_U8似乎是亮点，之前没有看到过。尝试在Android的源码中寻找它的定义，没找到。但是在标准的alsa-lib中找到了：
typedef enum _snd_pcm_format {125 SND_PCM_FORMAT_UNKNOWN = -1,127 SND_PCM_FORMAT_S8 = 0,129 SND_PCM_FORMAT_U8,131 SND_PCM_FORMAT_S16_LE,133 SND_PCM_FORMAT_S16_BE,135 SND_PCM_FORMAT_U16_LE,137 SND_PCM_FORMAT_U16_BE,139 SND_PCM_FORMAT_S24_LE,141 SND_PCM_FORMAT_S24_BE,143 SND_PCM_FORMAT_U24_LE,145 SND_PCM_FORMAT_U24_BE,147 SND_PCM_FORMAT_S32_LE,149 SND_PCM_FORMAT_S32_BE,151 SND_PCM_FORMAT_U32_LE,153 SND_PCM_FORMAT_U32_BE,155 SND_PCM_FORMAT_FLOAT_LE,157 SND_PCM_FORMAT_FLOAT_BE,159 SND_PCM_FORMAT_FLOAT64_LE,161 SND_PCM_FORMAT_FLOAT64_BE,163 SND_PCM_FORMAT_IEC958_SUBFRAME_LE,165 SND_PCM_FORMAT_IEC958_SUBFRAME_BE,167 SND_PCM_FORMAT_MU_LAW,169 SND_PCM_FORMAT_A_LAW,171 SND_PCM_FORMAT_IMA_ADPCM,173 SND_PCM_FORMAT_MPEG,175 SND_PCM_FORMAT_GSM,177 SND_PCM_FORMAT_SPECIAL = 31,179 SND_PCM_FORMAT_S24_3LE = 32,181 SND_PCM_FORMAT_S24_3BE,183 SND_PCM_FORMAT_U24_3LE,185 SND_PCM_FORMAT_U24_3BE,187 SND_PCM_FORMAT_S20_3LE,189 SND_PCM_FORMAT_S20_3BE,191 SND_PCM_FORMAT_U20_3LE,193 SND_PCM_FORMAT_U20_3BE,195 SND_PCM_FORMAT_S18_3LE,197 SND_PCM_FORMAT_S18_3BE,199 SND_PCM_FORMAT_U18_3LE,201 SND_PCM_FORMAT_U18_3BE,202 /* G.723 (ADPCM) 24 kbit/s, 8 samples in 3 bytes */203 SND_PCM_FORMAT_G723_24,204 /* G.723 (ADPCM) 24 kbit/s, 1 sample in 1 byte */205 SND_PCM_FORMAT_G723_24_1B,206 /* G.723 (ADPCM) 40 kbit/s, 8 samples in 3 bytes */207 SND_PCM_FORMAT_G723_40,208 /* G.723 (ADPCM) 40 kbit/s, 1 sample in 1 byte */209 SND_PCM_FORMAT_G723_40_1B,210 /* Direct Stream Digital (DSD) in 1-byte samples (x8) */211 SND_PCM_FORMAT_DSD_U8,212 /* Direct Stream Digital (DSD) in 2-byte samples (x16) */213 SND_PCM_FORMAT_DSD_U16_LE,214 SND_PCM_FORMAT_LAST = SND_PCM_FORMAT_DSD_U16_LE,215 216 #if __BYTE_ORDER == __LITTLE_ENDIAN217 218 SND_PCM_FORMAT_S16 = SND_PCM_FORMAT_S16_LE,220 SND_PCM_FORMAT_U16 = SND_PCM_FORMAT_U16_LE,222 SND_PCM_FORMAT_S24 = SND_PCM_FORMAT_S24_LE,224 SND_PCM_FORMAT_U24 = SND_PCM_FORMAT_U24_LE,226 SND_PCM_FORMAT_S32 = SND_PCM_FORMAT_S32_LE,228 SND_PCM_FORMAT_U32 = SND_PCM_FORMAT_U32_LE,230 SND_PCM_FORMAT_FLOAT = SND_PCM_FORMAT_FLOAT_LE,232 SND_PCM_FORMAT_FLOAT64 = SND_PCM_FORMAT_FLOAT64_LE,234 SND_PCM_FORMAT_IEC958_SUBFRAME = SND_PCM_FORMAT_IEC958_SUBFRAME_LE235 #elif __BYTE_ORDER == __BIG_ENDIAN236 237 SND_PCM_FORMAT_S16 = SND_PCM_FORMAT_S16_BE,239 SND_PCM_FORMAT_U16 = SND_PCM_FORMAT_U16_BE,241 SND_PCM_FORMAT_S24 = SND_PCM_FORMAT_S24_BE,243 SND_PCM_FORMAT_U24 = SND_PCM_FORMAT_U24_BE,245 SND_PCM_FORMAT_S32 = SND_PCM_FORMAT_S32_BE,247 SND_PCM_FORMAT_U32 = SND_PCM_FORMAT_U32_BE,249 SND_PCM_FORMAT_FLOAT = SND_PCM_FORMAT_FLOAT_BE,251 SND_PCM_FORMAT_FLOAT64 = SND_PCM_FORMAT_FLOAT64_BE,253 SND_PCM_FORMAT_IEC958_SUBFRAME = SND_PCM_FORMAT_IEC958_SUBFRAME_BE254 #else255 #error "Unknown endian"256 #endif257 } snd_pcm_format_t;
暂时还不知具体是怎么工作的，是透传DSD数据到硬件？还是alsa-lib中先转换为标准的PCM？ 但在Android的alsa-lib中，确实是没有SND_PCM_FORMAT_DSD的定义，应该是被精简掉了。因此只能考虑采用DSD->PCM转换成24bit 176K后，再按照标准的PCM方式来播放。
Android中播放DSD音乐
声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉： 投诉/举报 工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。