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• avcodec_encode_video returns 0 as output size

  11 juin 2014, par vacetahanna

  Hello what I am doing wrong ? When I try to encode a Frame, the out_size is 0. and if I use the avcodec_encode_video2 the return value is 0, which indicates, that everything went good, but the avpkt.size is 0 after that. What am I missing or doing wrong ? thank you so much here is my code

  int EncodeVideoFFMPEG::enc_main( void *istream, void *outstream, int width, int height )
  
  {
  
  
  
  avcodec_register_all();
  
  //choose codec
  
  AVCodec *codec = avcodec_find_encoder(CODEC_ID_H264);
  
  
  
  //set parameters
  
  AVCodecContext *c = avcodec_alloc_context3(codec);
  
  c->codec_type = AVMEDIA_TYPE_VIDEO;
  
  c->bit_rate = 50000;
  
  c->pix_fmt = PIX_FMT_YUV420P;
  
  c->width = width;
  
  c->height = height;
  
  c->time_base.num = 1;
  
  c->time_base.den = 25;
  
  c->gop_size = 20;
  
  c->max_b_frames = 0;
  
  
  
  //open
  
  avcodec_open2(c, codec, NULL);
  
  
  
  int got_packet;
  
  
  
  int BYTEPIC = width * height * 3;
  
  
  
  //prepare for changing color space
  
  struct SwsContext *img_convert_ctx1 =
  
  sws_getContext(width, height, PIX_FMT_BGR24,
  
  width, height, PIX_FMT_YUV420P,
  
  SWS_BICUBIC, NULL, NULL, NULL);
  
  
  
  //allocateframesforcolorspacechange
  
  AVFrame *pictureBGR = alloc_pictureBGR24(width, height);
  
  AVFrame *picture = alloc_picture420P(width, height);
  
  
  
  //get frame from OGRE and let pictureBGR point to it
  
  unsigned char *image = new unsigned char[BYTEPIC];
  
  memcpy(image, istream, BYTEPIC);
  
  
  
  //change from BGR to 420P
  
  sws_scale(img_convert_ctx1, &image, pictureBGR->linesize, 0, height, picture->data, picture->linesize);
  
  
  
  delete image;
  
  
  
  AVPacket avpkt;
  
  av_new_packet( &avpkt, BYTEPIC );
  
  
  
  //encode withthe codec
  
  int out_size = avcodec_encode_video(c, avpkt.data, avpkt.size, picture);
  
  //int success = avcodec_encode_video2(c, &avpkt, picture, &got_packet);  
  
  
  
  outstream = avpkt.data;
  
  
  
  return out_size;
  
  
  
      }

• libswresample : swr_convert() returns empty buffer

  11 septembre 2019, par Герман Лиманський

  I try to convert audio in format AV_SAMPLE_FMT_S32. I use swr_convert(), but out buffer still empty.

  // frame is decoded frame, rframe - is empty frame(out buffer)

      if (!main_context->resampler) {
  
                      main_context->resampler = 
  
                      swr_alloc_set_opts(main_context->resampler,
  
                      AV_CH_LAYOUT_STEREO,                    // output
  
                      AV_SAMPLE_FMT_S32,                      // output
  
                      44100,                                  // output
  
                      audio_codec_context->channel_layout,    // input
  
                      audio_codec_context->sample_fmt,        // input
  
                      audio_codec_context->sample_rate,       // input
  
                      0,
  
                      nullptr);
  
                  swr_init(main_context->resampler);
  
  
  
              }
  
  
  
              //int in_samples = frame->nb_samples;
  
              int out_samples = av_rescale_rnd(swr_get_delay(
  
                  main_context->resampler, 44100) + 44100,
  
                  44100,
  
                  44100,
  
                  AV_ROUND_UP);
  
  
  
              size_t buffSize = av_samples_alloc(rframe->data, NULL,audio_codec_context->channels, out_samples, AV_SAMPLE_FMT_S32, 0);
  
              int len = swr_convert(main_context->resampler, rframe->data, frame->nb_samples, (const uint8_t * *)frame->data, frame->nb_samples);
  
  //here.. rframe->data should have some data, but its empty
  
              while (len > 0)
  
              {
  
                  size_t size_ = rframe->nb_samples * av_get_bytes_per_sample(AV_SAMPLE_FMT_S32);
  
                  main_context->audio_buf.write(rframe->data[0], size_, 1);
  
  
  
                  len = swr_convert(main_context->resampler, rframe->data, frame->nb_samples, NULL, NULL);
  
              }

• Flash, Google, VP8, and the future of internet video

  23 février 2010, par Dark Shikari — H.264, HTML5, Theora, VP8, google, x264

  This is going to be a much longer post than usual, as it’s going to cover a lot of ground. The internet has been filled for quite some time with an enormous number of blog posts complaining about how Flash sucks–so much that it’s sounding as if the entire internet is crying wolf. But, of [...]