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• Extract all audio from a mov file into a aac file [closed]

  5 février 2024, par Sushrut Kaul

  I have a video which contains several streams as shown below :

  


  Stream #0:0[0x1](eng): Video: prores (XQ) (ap4x / 0x78347061), yuv444p12le(bt709/smpte432/smpte2084, progressive), 3840x2160, 1222881 kb/s, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 24k tbn (default)
    Metadata:
      creation_time   : 2022-08-26T22:20:26.000000Z
      handler_name    : Apple Video Media Handler
      vendor_id       : appl
      encoder         : Apple ProRes 4444 XQ
      timecode        : 00:59:59:00
    Side data:
      Content Light Level Metadata, MaxCLL=726, MaxFALL=93
  Stream #0:1[0x2](eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, 1 channels (FL), s32 (24 bit), 1152 kb/s (default)
    Metadata:
      creation_time   : 2022-08-26T22:20:26.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
  Stream #0:2[0x3](eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, 1 channels (FR), s32 (24 bit), 1152 kb/s (default)
    Metadata:
      creation_time   : 2022-08-26T22:20:26.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
  Stream #0:3[0x4](eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32 (24 bit), 1152 kb/s (default)
    Metadata:
      creation_time   : 2022-08-26T22:20:26.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
  Stream #0:4[0x5](eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, 1 channels (LFE), s32 (24 bit), 1152 kb/s (default)
    Metadata:
      creation_time   : 2022-08-26T22:20:26.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
  Stream #0:5[0x6](eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, 1 channels (BL), s32 (24 bit), 1152 kb/s (default)
    Metadata:
      creation_time   : 2022-08-26T22:20:26.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
  Stream #0:6[0x7](eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, 1 channels (BR), s32 (24 bit), 1152 kb/s (default)
    Metadata:
      creation_time   : 2022-08-26T22:20:26.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
  Stream #0:7[0x8](eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, 1 channels (DL), s32 (24 bit), 1152 kb/s (default)
    Metadata:
      creation_time   : 2022-08-26T22:20:26.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
  Stream #0:8[0x9](eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, 1 channels (DR), s32 (24 bit), 1152 kb/s (default)
    Metadata:
      creation_time   : 2022-08-26T22:20:26.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]


  


  As you can see, these audio streams are single channel as each stream is mapping to a unique channel.

  


  I want to combine these audio streams into a aac file such that the output has the channel information retained.

  


  I use the following command to do this :

  


  ffmpeg -i -filter _complex "[0:a:0][0:a:1][0:a:2][0:a:3][0:a:4][0:a:5][0:a:6][0:a:7]join=inputs=8:channel_layout=7.1[aout]" -map "[aout]" -c:a aac output_audio_join.aac

  


  The individual audio streams were having a duration of duration=103.728625 seconds.

  


  The output however is 862.207660 seconds. Why ?

  


• Encoding raw YUV420P to h264 with AVCodec on iOS

  4 janvier 2013, par Wade

  I am trying to encode a single YUV420P image gathered from a CMSampleBuffer to an AVPacket so that I can send h264 video over the network with RTMP.

  The posted code example seems to work as avcodec_encode_video2 returns 0 (Success) however got_output is also 0 (AVPacket is empty).

  Does anyone have any experience with encoding video on iOS devices that might know what I am doing wrong ?

  - (void) captureOutput:(AVCaptureOutput *)captureOutput
  
   didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
  
          fromConnection:(AVCaptureConnection *)connection {
  
  
  
    // sampleBuffer now contains an individual frame of raw video frames
  
    CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
  
  
  
    CVPixelBufferLockBaseAddress(pixelBuffer, 0);
  
  
  
    // access the data
  
    int width = CVPixelBufferGetWidth(pixelBuffer);
  
    int height = CVPixelBufferGetHeight(pixelBuffer);
  
    int bytesPerRow = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 0);
  
    unsigned char *rawPixelBase = (unsigned char *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);
  
  
  
  
  
    // Convert the raw pixel base to h.264 format
  
    AVCodec *codec = 0;
  
    AVCodecContext *context = 0;
  
    AVFrame *frame = 0;
  
    AVPacket packet;
  
  
  
    //avcodec_init();
  
    avcodec_register_all();
  
    codec = avcodec_find_encoder(AV_CODEC_ID_H264);
  
  
  
    if (codec == 0) {
  
      NSLog(@"Codec not found!!");
  
      return;
  
    }
  
  
  
    context = avcodec_alloc_context3(codec);
  
  
  
    if (!context) {
  
      NSLog(@"Context no bueno.");
  
      return;
  
    }
  
  
  
    // Bit rate
  
    context->bit_rate = 400000; // HARD CODE
  
    context->bit_rate_tolerance = 10;
  
    // Resolution
  
    context->width = width;
  
    context->height = height;
  
    // Frames Per Second
  
    context->time_base = (AVRational) {1,25};
  
    context->gop_size = 1;
  
    //context->max_b_frames = 1;
  
    context->pix_fmt = PIX_FMT_YUV420P;
  
  
  
    // Open the codec
  
    if (avcodec_open2(context, codec, 0) < 0) {
  
      NSLog(@"Unable to open codec");
  
      return;
  
    }
  
  
  
  
  
    // Create the frame
  
    frame = avcodec_alloc_frame();
  
    if (!frame) {
  
      NSLog(@"Unable to alloc frame");
  
      return;
  
    }
  
    frame->format = context->pix_fmt;
  
    frame->width = context->width;
  
    frame->height = context->height;
  
  
  
  
  
    avpicture_fill((AVPicture *) frame, rawPixelBase, context->pix_fmt, frame->width, frame->height);
  
  
  
    int got_output = 0;
  
    av_init_packet(&packet);
  
    avcodec_encode_video2(context, &packet, frame, &got_output)
  
  
  
    // Unlock the pixel data
  
    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
  
    // Send the data over the network
  
    [self uploadData:[NSData dataWithBytes:packet.data length:packet.size] toRTMP:self.rtmp_OutVideoStream];
  
  }

  Note : It is known that this code has memory leaks because I am not freeing the memory that is dynamically allocated.

  UPDATE

  I updated my code to use @pogorskiy method. I only try to upload the frame if got output returns 1 and clear the buffer once I am done encoding video frames.

• rtpdec : Don’t pass non-const pointers to fmtp attribute parsing functions

  24 février 2015, par Martin Storsjö

  rtpdec : Don’t pass non-const pointers to fmtp attribute parsing functions
  This makes it clear that the individual parsing functions can’t
  
  touch the parsed out value.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavformat/rtpdec.c
  • [DH] libavformat/rtpdec.h
  • [DH] libavformat/rtpdec_amr.c
  • [DH] libavformat/rtpdec_dv.c
  • [DH] libavformat/rtpdec_h264.c
  • [DH] libavformat/rtpdec_hevc.c
  • [DH] libavformat/rtpdec_ilbc.c
  • [DH] libavformat/rtpdec_latm.c
  • [DH] libavformat/rtpdec_mpeg4.c
  • [DH] libavformat/rtpdec_xiph.c