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• Android how to increase ffmpeg mp4 perfromance ?

  4 janvier 2013, par testCoder

  I have detected that function avcodec_decode_audio3 works slow with mp4 format, here my code cycle for decoding audio :

  while (av_read_frame(av_format_context, &packet) >= 0 && is_play == 1) {
  
          if (av_codec_context->codec_type == AVMEDIA_TYPE_AUDIO
  
                  && is_play == 1) {
  
              int out_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
  
              int size = packet.size;
  
              int n;
  
              int dataLength = size;
  
              int decoded = 0;
  
              while (size > 0) {
  
  
  
                  //start measure time
  
                  gettimeofday(&tvBegin, NULL);
  
  
  
                  int len = avcodec_decode_audio3(av_codec_context,
  
                          (int16_t *) pAudioBuffer, &out_size, &packet);
  
  
  
                  //stop measure time
  
                  gettimeofday(&tvEnd, NULL);
  
                  timeval_subtract(&tvDiff, &tvEnd, &tvBegin);
  
  
  
                  LOGI("%d", tvDiff.tv_usec / 1000);
  
                  LOGI("len='%d'", len);
  
                  LOGI("out_size='%d'", out_size);
  
  
  
                  if (len < 0) {
  
                      break;
  
                      return 1;
  
                  }
  
                  if (out_size > 0) {
  
  
  
  
  
  
  
                      jbyte *bytes = (*env)->GetByteArrayElements(env, array,
  
                              NULL);
  
                      memcpy(bytes, (int16_t *) pAudioBuffer, out_size);
  
                      (*env)->ReleaseByteArrayElements(env, array, bytes, 0);
  
                      (*env)->CallVoidMethod(env, obj, play, array, out_size,
  
                              is_play);
  
  
  
                  }
  
                  size -= len;
  
              }
  
  
  
          }
  
          if (packet.data)
  
              av_free_packet(&packet);
  
  
  
      }

  But with other formats like flac and mp3 it works fine. avcodec_decode_audio3 take about 1-2 milisecounds for decoding mp3 frame with out_size = 4608 but with the same frame size in mp4 decoding take about 6-7 millisecounds. I got my build script from here.

  Does it normal behavior ? Is any way to increase performance of decoding mp4 ?

• FFMPEG x264 encoding on Android - error with lookahead

  6 janvier 2013, par Tishu

  I am using FFMPEG + x264 on Android to encode YUV420 frames to a video file. I use the following code on each frame to encode them :

  avcodec_encode_video2(gVideoWriteCodecCtx, &packet, pCurrentFrame, &gotPacket);

  On the first few calls, the frame buffer gets filled and nothing is encoded. When the first encoding happens, a call is made to x264_lookahead_get_frames. I can see there that my frame array is correctly populated, but the first item is NULL. As a consequence, in x264_weights_analyse the reference frame gotten as frames[p0] is NULL and I get an exception there.

  slicetype.c, the first frame in "frames" is NULL

  if( h->param.analyse.i_weighted_pred && b == p1 )
  
      {
  
          x264_emms();
  
          x264_weights_analyse( h, fenc, frames[p0], 1 );
  
          w = fenc->weight[0];
  
      }

  And the exception happens there, ref is NULL

  static void x264_weights_analyse( x264_t *h, x264_frame_t *fenc, x264_frame_t *ref, int b_lookahead )
  
      {
  
          int i_delta_index = fenc->i_frame - ref->i_frame - 1;

  I surely am missing something as I am sure this encoder works for most people :) Does anyone have an idea why this first frame in the "frames" array is null ?

  Many thanks

• FFMPEG x264 encoding on Android - error with lookahead

  6 janvier 2013, par Tishu

  I am using FFMPEG + x264 on Android to encode YUV420 frames to a video file. I use the following code on each frame to encode them :

  avcodec_encode_video2(gVideoWriteCodecCtx, &packet, pCurrentFrame, &gotPacket);

  On the first few calls, the frame buffer gets filled and nothing is encoded. When the first encoding happens, a call is made to x264_lookahead_get_frames. I can see there that my frame array is correctly populated, but the first item is NULL. As a consequence, in x264_weights_analyse the reference frame gotten as frames[p0] is NULL and I get an exception there.

  slicetype.c, the first frame in "frames" is NULL

  if( h->param.analyse.i_weighted_pred && b == p1 )
  
      {
  
          x264_emms();
  
          x264_weights_analyse( h, fenc, frames[p0], 1 );
  
          w = fenc->weight[0];
  
      }

  And the exception happens there, ref is NULL

  static void x264_weights_analyse( x264_t *h, x264_frame_t *fenc, x264_frame_t *ref, int b_lookahead )
  
      {
  
          int i_delta_index = fenc->i_frame - ref->i_frame - 1;

  I surely am missing something as I am sure this encoder works for most people :) Does anyone have an idea why this first frame in the "frames" array is null ?

  Many thanks