/*************************************************************************** *  FFmpeg  ‘scale‘ filter not present, cannot convert pixel formats. * 说明： *     使用FFmpeg的过程中遇到这个问题，记录一下解决办法。 * *                                      2017-2-6 深圳 南山平山村 曾剑锋 **************************************************************************/一、参考文档：    1. 支持各类音频格式的ffmpeg静态编译        http://andremouche.github.io/ffmpeg/ffmpeg-audio.html    2. How do I use ffmpeg to take pictures with my web camera?        http://askubuntu.com/questions/102755/how-do-i-use-ffmpeg-to-take-pictures-with-my-web-camera二、出错现象：    # ffmpeg -y  -r 25 -i /dev/video1 out.mp4    ffmpeg version 3.2 Copyright (c) 2000-2016 the FFmpeg developers      built with gcc 4.8.3 (Sourcery CodeBench Lite 2014.05-29) 20140320 (prerelease)      configuration: --enable-cross-compile --cross-prefix=/home/zengjf/tinyfs/buildroot-2016.11.1/output/host/usr/bin/arm-none-linux-gnueabi- --sysroot=/home/zengjf/tinyfs/buildroot-2016.11.1/output/host/usr/arm-buildroot-linux-gnueabi/sysroot --host-cc=/usr/bin/gcc --arch=arm --target-os=linux --disable-stripping --pkg-config=/home/zengjf/tinyfs/buildroot-2016.11.1/output/host/usr/bin/pkg-config --disable-static --enable-shared --prefix=/usr --enable-avfilter --disable-version3 --enable-logging --enable-optimizations --disable-extra-warnings --enable-avdevice --enable-avcodec --enable-avformat --disable-x11grab --enable-network --disable-gray --enable-swscale-alpha --disable-small --enable-dct --enable-fft --enable-mdct --enable-rdft --disable-crystalhd --disable-dxva2 --enable-runtime-cpudetect --disable-hardcoded-tables --disable-memalign-hack --disable-mipsdsp --disable-mipsdspr2 --disable-msa --enable-hwaccels --disable-avisynth --disable-frei0r --disable-libopencore-amrnb --disable-libopencore-amrwb --disable-libcdio --disable-libdc1394 --disable-libgsm --disable-libilbc --disable-libnut --disable-libopenjpeg --disable-libschroedinger --disable-libvo-amrwbenc --disable-symver --disable-doc --disable-gpl --disable-nonfree --enable-ffmpeg --disable-ffplay --disable-ffserver --disable-avresample --disable-ffprobe --disable-postproc --disable-swscale --enable-indevs --enable-outdevs --enable-pthreads --enable-zlib --enable-bzlib --disable-libfdk-aac --disable-gnutls --enable-openssl --disable-libopenh264 --disable-vaapi --disable-vdpau --disable-libopencv --disable-libopus --disable-libvpx --disable-libass --disable-libbluray --disable-librtmp --disable-libmp3lame --disable-libmodplug --disable-libspeex --disable-libtheora --disable-libwavpack --disable-libfreetype --disable-fontconfig --disable-libx264 --disable-libx265 --disable-yasm --disable-mmx --disable-sse --disable-sse2 --disable-sse3 --disable-ssse3 --disable-sse4 --disable-sse42 --disable-avx --disable-avx2 --enable-armv6 --disable-vfp --disable-neon --disable-altivec --enable-pic --cpu=cortex-a9      libavutil      55. 34.100 / 55. 34.100      libavcodec     57. 64.100 / 57. 64.100      libavformat    57. 56.100 / 57. 56.100      libavdevice    57.  1.100 / 57.  1.100      libavfilter     6. 65.100 /  6. 65.100      libswresample   2.  3.100 /  2.  3.100    Input #0, video4linux2,v4l2, from ‘/dev/video1‘:      Duration: N/A, start: 1111.503970, bitrate: 147456 kb/s        Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 640x480, 147456 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc    ‘scale‘ filter not present, cannot convert pixel formats.    Error opening filters!    # 三、解决方法：    编译时添加scale的支持:        --enable-swscale --enable-swscale-alpha --enable-filter=scale