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• How to handle queueing of video encoding during multiple video uploads ?

  6 mars 2016, par Yash Desai

  I am working on developing a video streaming site where users can upload videos to the site (multiple videos at once using the uploadify jquery plugin).

  Now, I am faced with the question of encoding the videos to FLV for streaming them online.

  When should the video encoding process take place ? Should it take place immediately after uploads have finished (i.e redirect the user to upload success page, and then start encoding in the background using exec command for ffmpeg ?) However, using this approach, how do i determine if the encoding has finished successfully ? What if users upload a corrupt video and ffmpeg fails to encode it ? How do i handle this in PHP ?

  How do i queue encoding of videos since multiple users can upload videos at the same ? Does FFMpeg has its own encoding queue ?

  I also read about gearman and message queueing options such as redis and AMQP in another related SO thread. Are these one of the potential solutions ?

  I would really appreciate if someone could give answers to my questions.

• Rendering Bitmap using ANativeWindow

  19 février 2016, par William Seemann

  I’m decoding a video frame and trying to render is using Android’s ANativeWindow API in conjunction with a SurfaceView. I know I’m decoding the frame successfully because my demo application returns the decoded (and re-encoded) frame as a bitmap and displays it in an ImageView (bottom image). However, when trying to draw the decoded frame to a SurfaceView I’m getting garbage output (top image). Can someone explain why ?

  const int TARGET_IMAGE_FORMAT = AV_PIX_FMT_RGBA;
  
  const int TARGET_IMAGE_CODEC = AV_CODEC_ID_PNG;
  
  
  
  void convert_image(State *state, AVCodecContext *pCodecCtx, AVFrame *pFrame, AVPacket *avpkt, int *got_packet_ptr, int width, int height) {
  
          AVCodecContext *codecCtx;
  
          AVCodec *codec;
  
          AVFrame *frame;
  
  
  
          *got_packet_ptr = 0;
  
  
  
          if (width == -1) {
  
              width = pCodecCtx->width;
  
          }
  
  
  
          if (height == -1) {
  
              height = pCodecCtx->height;
  
          }
  
  
  
          codec = avcodec_find_encoder(TARGET_IMAGE_CODEC);
  
          if (!codec) {
  
              printf("avcodec_find_decoder() failed to find decoder\n");
  
              goto fail;
  
          }
  
  
  
          codecCtx = avcodec_alloc_context3(codec);
  
          if (!codecCtx) {
  
              printf("avcodec_alloc_context3 failed\n");
  
              goto fail;
  
          }
  
  
  
          codecCtx->bit_rate = pCodecCtx->bit_rate;
  
          //codecCtx->width = pCodecCtx->width;
  
          //codecCtx->height = pCodecCtx->height;
  
          codecCtx->width = width;
  
          codecCtx->height = height;
  
          codecCtx->pix_fmt = TARGET_IMAGE_FORMAT;
  
          codecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
  
          codecCtx->time_base.num = pCodecCtx->time_base.num;
  
          codecCtx->time_base.den = pCodecCtx->time_base.den;
  
  
  
          if (!codec || avcodec_open2(codecCtx, codec, NULL) < 0) {
  
              printf("avcodec_open2() failed\n");
  
              goto fail;
  
          }
  
  
  
          frame = av_frame_alloc();
  
  
  
          if (!frame) {
  
              goto fail;
  
          }
  
  
  
          // Determine required buffer size and allocate buffer
  
          int numBytes = avpicture_get_size(TARGET_IMAGE_FORMAT, codecCtx->width, codecCtx->height);
  
          void * buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));
  
  
  
          printf("wqwq %d\n", numBytes);
  
  
  
          avpicture_fill(((AVPicture *)frame),
  
                  buffer,
  
                  TARGET_IMAGE_FORMAT,
  
                  codecCtx->width,
  
                  codecCtx->height);
  
  
  
          avpicture_alloc(((AVPicture *)frame),
  
                  TARGET_IMAGE_FORMAT,
  
                  codecCtx->width,
  
                  codecCtx->height);
  
  
  
          struct SwsContext *scalerCtx = sws_getContext(pCodecCtx->width, 
  
                  pCodecCtx->height, 
  
                  pCodecCtx->pix_fmt,
  
                  //pCodecCtx->width,
  
                  //pCodecCtx->height,
  
                  width,
  
                  height,
  
                  TARGET_IMAGE_FORMAT, 
  
                  SWS_FAST_BILINEAR, 0, 0, 0);
  
  
  
          if (!scalerCtx) {
  
              printf("sws_getContext() failed\n");
  
              goto fail;
  
          }
  
  
  
          sws_scale(scalerCtx,
  
                  (const uint8_t * const *) pFrame->data,
  
                  pFrame->linesize,
  
                  0,
  
                  pFrame->height,
  
                  frame->data,
  
                  frame->linesize);
  
  
  
          int ret = avcodec_encode_video2(codecCtx, avpkt, frame, got_packet_ptr);
  
  
  
          // code to draw the re-encoded frame on the surface view
  
          if (state->native_window) {    
  
              ANativeWindow_Buffer windowBuffer;
  
  
  
              if (ANativeWindow_lock(state->native_window, &windowBuffer, NULL) == 0) {
  
                  memcpy(windowBuffer.bits, avpkt->data, windowBuffer.width * windowBuffer.height * 4);
  
                  ANativeWindow_unlockAndPost(state->native_window);
  
              }
  
          }
  
  
  
          if (ret < 0) {
  
              *got_packet_ptr = 0;
  
          }
  
  
  
          fail:
  
          av_free(frame);
  
  
  
          free(buffer);
  
  
  
          if (codecCtx) {
  
              avcodec_close(codecCtx);
  
              av_free(codecCtx);
  
          }
  
  
  
          if (scalerCtx) {
  
              sws_freeContext(scalerCtx);
  
          }
  
  
  
          if (ret < 0 || !*got_packet_ptr) {
  
              av_free_packet(avpkt);
  
          }
  
      }

  

• x86inc : Add debug symbols indicating sizes of compiled functions

  18 janvier 2016, par Geza Lore

  x86inc : Add debug symbols indicating sizes of compiled functions
  Some debuggers/profilers use this metadata to determine which function a
  
  given instruction is in ; without it they get can confused by local labels
  
  (if you haven’t stripped those). On the other hand, some tools are still
  
  confused even with this metadata. e.g. this fixes `gdb`, but not `perf`.
  Currently only implemented for ELF.
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DBH] libavcodec/x86/proresdsp.asm
  • [DBH] libavutil/x86/x86inc.asm
  • [DBH] tests/checkasm/x86/checkasm.asm