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• ffmpeg / libav encoding 264 from YUV420P [on hold]

  4 janvier 2017, par MrSmith

  I am having issues getting this thing to encode correctly. Either I get the container wrong or the content it seems.
  This code encodes a file just fine, but viewing it with VLC or Totem will just yield the first picture, not the remaining 100 frames.
  This is a step up from before as I dont get warnings that my container (mp4) is borked, however now the video wont play at all.. at least it played before :).

  If someone could put a finger somewhere on this code and call me a dumbass, that would be nice :)

  void encode_video(char *carrarr[]){
  
  av_log_set_level(AV_LOG_DEBUG);
  
  av_register_all();
  
  avcodec_register_all();
  
  AVCodec *codec = avcodec_find_encoder(AV_CODEC_ID_H264);
  
  AVOutputFormat * outputFormat = av_guess_format("mp4", NULL, NULL);
  
  
  
  int test = avformat_alloc_output_context2(&outFmtCtx, outputFormat, NULL, NULL);
  
  if(test<0) exit(-1);
  
  
  
  AVStream * outStrm = avformat_new_stream(outFmtCtx, codec);
  
  avcodec_get_context_defaults3(outStrm->codec, codec);
  
  
  
  outStrm->codec->codec_id = AV_CODEC_ID_H264;
  
  outStrm->codec->coder_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  outStrm->codec->bit_rate = 400000;
  
  outStrm->codec->width = 320;
  
  outStrm->codec->height = 240;
  
  outStrm->codec->time_base= (AVRational){1,25};
  
  outStrm->time_base=(AVRational){1,25};
  
  outStrm->codec->gop_size = 10; // emit one intra frame every ten frames
  
  outStrm->codec->max_b_frames=1;
  
  outStrm->codec->pix_fmt = AV_PIX_FMT_YUV420P;
  
  outStrm->codec->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
  
  // FOR H264 ONLY
  
  test = av_opt_set(outStrm->codec->priv_data, "preset", "slow", 0);
  
  if(test<0) exit(-2);
  
  test = avcodec_open2(outStrm->codec, codec, NULL);
  
  if(test<0) exit(-3);
  
  test = avio_open2(&outFmtCtx->pb, "myoutputfile.avi", AVIO_FLAG_WRITE, NULL, NULL);
  
  if(test<0) exit(-4);
  
  
  
  test = avformat_write_header(outFmtCtx, NULL);
  
  if(test<0) exit(-5);
  
  AVFrame * frame = avcodec_alloc_frame();
  
  if (!frame) exit(-6);
  
  
  
  frame->format = outStrm->codec->pix_fmt;
  
  frame->width  = outStrm->codec->width;
  
  frame->height = outStrm->codec->height;
  
  
  
  ret = av_image_alloc(frame->data, frame->linesize, frame->width, frame->height, outStrm->codec->pix_fmt, 32);
  
  if (ret < 0) exit(-7);
  
  
  
  av_init_packet(&pkt);
  
  pkt.data = NULL;
  
  pkt.size = 0;
  
  
  
  int yrange = 240*320;
  
  int vrange = 240*320*0.25;
  
  
  
  for(int i=0;i<100;i++){
  
      char *carr = carrarr[i];
  
  
  
      char* Y = carr;
  
      char* U = carr+yrange;
  
      char* V = carr+yrange+vrange;
  
      frame->data[0] = (uint8_t*)Y;
  
      frame->data[1] = (uint8_t*)U;
  
      frame->data[2] = (uint8_t*)V;
  
      frame->pts = i;
  
  
  
      ret = avcodec_encode_video2(outStrm->codec, &pkt, frame, &got_output);
  
      if (ret < 0) {
  
          fprintf(stderr, "Error encoding frame\n");
  
          exit (EXIT_FAILURE);
  
      }
  
      if (got_output) {
  
          printf("Write frame %3d (size=%5d)\n", i, pkt.size);
  
          //fwrite(pkt.data, 1, pkt.size, file_encoded_video);
  
          av_interleaved_write_frame(outFmtCtx, &pkt);
  
          av_free_packet(&pkt);
  
      }
  
  }
  
  av_write_trailer(outFmtCtx);
  
  avio_close(outFmtCtx->pb);
  
  }

  carrarr is holding 100 frames of nice valid YUV420P data, I know this cause I’ve encoded it before AND I can output it to screen with SDL.

  Any ideas welcome. Thanks !

• Error in video streaming using libavformat : VBV buffer size not set, muxing may fail

  18 octobre 2017, par Blue Sky

  I stream a video using libavformat as follows :

  static AVStream *add_stream(AVFormatContext *oc, AVCodec **codec,
  
                          enum AVCodecID codec_id)
  
  {
  
  AVCodecContext *c;
  
  AVStream *st;
  
  /* find the encoder */
  
  *codec = avcodec_find_encoder(codec_id);
  
  if (!(*codec)) {
  
      fprintf(stderr, "Could not find encoder for '%s'\n",
  
              avcodec_get_name(codec_id));
  
      exit(1);
  
  }
  
  st = avformat_new_stream(oc, *codec);
  
  if (!st) {
  
      fprintf(stderr, "Could not allocate stream\n");
  
      exit(1);
  
  }
  
  st->id = oc->nb_streams-1;
  
  c = st->codec;
  
  switch ((*codec)->type) {
  
  case AVMEDIA_TYPE_AUDIO:
  
      c->sample_fmt  = (*codec)->sample_fmts ?
  
          (*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
  
      c->bit_rate    = 64000;
  
      c->sample_rate = 44100;
  
      c->channels    = 2;
  
      break;
  
  case AVMEDIA_TYPE_VIDEO:
  
      c->codec_id = codec_id;
  
      c->bit_rate = 400000;
  
      /* Resolution must be a multiple of two. */
  
      c->width    = outframe_width;
  
      c->height   = outframe_height;
  
      /* timebase: This is the fundamental unit of time (in seconds) in terms
  
       * of which frame timestamps are represented. For fixed-fps content,
  
       * timebase should be 1/framerate and timestamp increments should be
  
       * identical to 1. */
  
      c->time_base.den = STREAM_FRAME_RATE;
  
      c->time_base.num = 1;
  
      c->gop_size      = 12; /* emit one intra frame every twelve frames at most */
  
      c->pix_fmt       = STREAM_PIX_FMT;
  
      if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
  
          /* just for testing, we also add B frames */
  
          c->max_b_frames = 2;
  
      }
  
      if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
  
          /* Needed to avoid using macroblocks in which some coeffs overflow.
  
           * This does not happen with normal video, it just happens here as
  
           * the motion of the chroma plane does not match the luma plane. */
  
          c->mb_decision = 2;
  
      }
  
  break;
  
  default:
  
      break;
  
  }
  
  /* Some formats want stream headers to be separate. */
  
  if (oc->oformat->flags & AVFMT_GLOBALHEADER)
  
      c->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  return st;
  
  }

  But when I run this code, I get the following error/warning :

  [mpeg @ 01f3f040] VBV buffer size not set, muxing may fail

  Do you know how I can set the VBV buffer size in the code ? In fact, when I use ffplay to display the streamed video, ffplay doesn’t show anything for short videos but for long videos, it start displaying the video immediately. So, it looks like ffplay needs a buffer to be filled up by some amount so that it can start displaying the stream. Am I right ?

• Encoding RGB frames using x264 and AVCodec in C

  6 novembre 2016, par deepwork

  I have RGB24 frames streamed from camera and i want to encode them into h264 ,i found that AVCodec and x264 can do so, the problem is x264 as default accepts YUV420 as input so what i wrote was a program which convert RGB frames to YUV420 .that was by sws_scale function .this works well except that it does not satisfy the required FPS because the converting (RGB->YUV420) takes time.

  This is how i setup my encoder context :

  videoStream->id = 0;
  
  vCodecCtx = videoStream->codec;
  
  
  
  vCodecCtx->coder_type       = AVMEDIA_TYPE_VIDEO;
  
  vCodecCtx->codec_id         = AV_CODEC_ID_H264;
  
  vCodecCtx->bit_rate         = 400000;
  
  vCodecCtx->width            = Width;
  
  vCodecCtx->height           = Height;
  
  vCodecCtx->time_base.den    = FPS;
  
  vCodecCtx->time_base.num    = 1;
  
  //vCodecCtx->time_base      = (AVRational){1,};
  
  vCodecCtx->gop_size         = 12;
  
  vCodecCtx->max_b_frames     = 1;
  
  vCodecCtx->pix_fmt          = AV_PIX_FMT_YUV420P;
  
  
  
  if(formatCtx->oformat->flags & AVFMT_GLOBALHEADER)
  
      vCodecCtx->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
  av_opt_set(vCodecCtx->priv_data, "preset", "ultrafast", 0);
  
  av_opt_set(vCodecCtx->priv_data, "profile", "baseline", AV_OPT_SEARCH_CHILDREN);
  
  
  
  if (avcodec_open2(vCodecCtx, h264Codec, NULL) < 0){
  
      return 0;
  
  }

  when i changes AV_PIX_FMT_YUV420P to AV_PIX_FMT_RGB24 ,avcodec_open2 will fail.
  i read that there is a version of libx264 for RGB called libx264rgb but i even dont know whether i have to rebuild x264 with enabling this option or to download another source or i have to do it programmatically with the first x264 lib.

  the question is how to enable RGB as input to libx264 to use with libavcodec in C .or how to make the encoding or sws_scale more fast .

  Edit :

  How i built ffmpeg :

  NDK=D:/AndroidDev/android-ndk-r9
  
  PLATFORM=$NDK/platforms/android-18/arch-arm/
  
  PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64
  
  
  
  GENERAL="\
  
  --enable-small \
  
  --enable-cross-compile \
  
  --extra-libs="-lgcc" \
  
  --arch=arm \
  
  --cc=$PREBUILT/bin/arm-linux-androideabi-gcc \
  
  --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \
  
  --nm=$PREBUILT/bin/arm-linux-androideabi-nm \
  
  --extra-cflags="-I../x264/android/arm/include" \
  
  --extra-ldflags="-L../x264/android/arm/lib" "
  
  
  
  
  
  MODULES="\
  
  --enable-gpl \
  
  --enable-libx264"
  
  
  
  function build_ARMv6
  
  {
  
    ./configure \
  
    --target-os=linux \
  
    --prefix=./android/armeabi \
  
    ${GENERAL} \
  
    --sysroot=$PLATFORM \
  
    --enable-shared \
  
    --disable-static \
  
    --extra-cflags=" -O3 -fpic -fasm -Wno-psabi -fno-short-enums -fno-strict-aliasing -finline-limit=300 -mfloat-abi=softfp -mfpu=vfp -marm -march=armv6" \
  
    --extra-ldflags="-lx264 -Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib -lc -lm -ldl -llog" \
  
    --enable-zlib \
  
    ${MODULES} \
  
    --disable-doc \
  
    --enable-neon
  
  
  
    make clean
  
    make
  
    make install
  
  }
  
  
  
  build_ARMv6
  
  
  
  echo Android ARMEABI builds finished

  How i built x264 :

  NDK=D:/AndroidDev/android-ndk-r9
  
  PLATFORM=$NDK/platforms/android-18/arch-arm/
  
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64
  
  PREFIX=./android/arm
  
  
  
  function build_one
  
  {
  
    ./configure \
  
    --prefix=$PREFIX \
  
    --enable-static \
  
    --enable-pic \
  
    --host=arm-linux \
  
    --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  
    --sysroot=$PLATFORM
  
  
  
    make clean
  
    make
  
    make install
  
  }
  
  
  
  build_one
  
  
  
  echo Android ARM builds finished