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• ffmpeg : sws_scale not able to convert image from YUV to RGB

  1er octobre 2020, par Abhinav Singh

  I m trying to convert my image from YUV420P to RGB24 below is my code for extracting the frame and decoding it,

  


  frame extracting

  


  while(av_read_frame(avc,avpacket) == 0){
        if(avpacket->stream_index == videoStream){
            int res = avcodec_send_packet(avctx,avpacket);
            if(res == AVERROR(EAGAIN)){
                continue;
            }
            else if(res<0){
                std::cout<<"error reading packet\n";
                break;
            }
            else{
                AVFrame* avframeRGB = av_frame_alloc();
                res = avcodec_receive_frame(avctx,avframeRGB);
                if(res == AVERROR(EAGAIN)){
                    continue;
                }
                else if(res<0){
                    std::cout<<"Error reading frame";
                    break;
                }
                else{
                    ++i;
                    convertImage(&avframeRGB,avctx->pix_fmt,AV_PIX_FMT_RGB24);
                    displayImage(avframeRGB);
                }
            }
        }
    }


  


  Function convertImage

  


  void convertImage(AVFrame** frame, AVPixelFormat srcFmt, AVPixelFormat destFmt){
    AVFrame* tframe = *frame;
    struct SwsContext* swscaler = sws_getContext(tframe->width,tframe->height,srcFmt,tframe->width,tframe->height,destFmt, SWS_BILINEAR,NULL,NULL,NULL);
    AVFrame* tmp = av_frame_alloc();
    tmp->width = tframe->width;
    tmp->height = tframe->height;
    tmp->format = destFmt;
    if(av_frame_get_buffer(tmp,32) !=0)
        return;
    int res = sws_scale(swscaler,(uint8_t const * const*)tframe->data,tframe->linesize,0,tframe->height,tmp->data,tmp->linesize);
    *frame = tmp;
}


  


  Before calling convertImage
avframeRGB

  


  data : {0x555555988ec0 &#x27;\020&#x27; <repeats 200="200" times="times">..., 0x555555a6f940 &#x27;\200&#x27; <repeats 200="200" times="times">..., 0x555555aa9440 &#x27;\200&#x27; <repeats 200="200" times="times">..., 0x0, 0x0, 0x0, 0x0, 0x0}&#xA;height : 720&#xA;width : 1280&#xA;</repeats></repeats></repeats>

  


  after calling convertImage

  


  data : {0x7fffdde19040 "", 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}
height : 0
width : 0


  


  I m not able to understand why my data is NULL and my height and width is 0 ?

  


  ffmpeg version - 4.3.2

  


• Random PIPELINE_ERROR_DECODE : video decoder reinitialization failed on Chromium HTML5 video tag

  9 janvier 2024, par Hello World

  System

  


  Running an Expo React Native app, with a <webview></webview> component that loads a NextJS app with an HTML5 <video></video> tag. The system with issues is running the app on Android 9.0 with WebView implementation set to Android System WebView 84.0. The system without issues is running the app on Android 10.0 with WebView implementation set to Android System WebView 120.0.

  


  Details

  


  Video files being played by the <video></video> element are previously transcoded by the following fluent-ffmpeg node package :

  


  import ffmpeg from 'fluent-ffmpeg'

ffmpeg(rawVideoFileUrl)
  .videoCodec('libx264')
  .audioCodec('aac')
  .outputOption('-strict experimental')
  .outputOption('-movflags frag_keyframe+faststart')
  .format('mp4')


  


  My knowledge on video transcoding is very limited, but I have to do the transcoding to guarantee that the files are compatible to be played by my NextJS web app. In my research, my findings pointed to these FFMPEG command line arguments for my purpose.

  


  For the aforementioned WebView version, H.264 with AAC, should be compatible, yet playback is not stable. Many times it will play just fine, but other times I receive the error :

  


  PIPELINE_ERROR_DECODE: video decoder reinitialization failed


  


  If I refresh the web app, it works again. That leads me to believe it is somehow memory related, maybe caused by incompatibility.

  


  I'm not sure whether video decoder reinitialization failed produced by the HTML5 <video></video> tag is a problem of transcoding or not, as the videos play fine most of the time and only produces that error in the console some of the times, unexpectedly.

  


  Question

  


  Is there something that I can do to the fluent-ffmpeg command to make the video files more widely compatible, including the WebView 84.0 system too, or is the issue somewhere else ?

  


  In this case, updating WebView is not an option.

  


• How would I add an audio channel to an rtsp stream ?

  9 septembre 2022, par PlayerWet

  Good companions. It turns out that my Raspberry does not give more than itself when it comes to joining video with audio at good quality and sending it by rtsp. But I think I could send the video in rtsp format and then the audio in mp3, but I would need to join it again on another computer (nas Debian) on my home lan where I have the Shinobi program (security camera manager) installed.

  


  I would need something that can somehow grab the rtsp stream and another mp3 audio and merge them into a new rtsp stream. Is this possible ? or is it a crazy idea.

  


  On the one hand I send this, which is the transmission of the camera by rtsp through v4l2rtspserver :

  


  v4l2rtspserver -H 1080 -W 1920 -F 25 -P 8555 /dev/video0


  


  And separately I send an audio in mp3 with sound from a usb microphone through ffmpeg :

  


  ffmpeg -ac 1 -f alsa -i hw:1,0 -acodec libmp3lame -ab 32k -ac 1 -f rtp rtp://192.168.1.77:12348


  


  My idea is to put both things together on a nas server in a new rtsp stream (or another idea).

  


  But I don't know if with ffmpeg I can capture the video from an rtsp video stream and then be able to join it with the mp3 audio and form another new rtsp stream.

  


  Merge these two streams into one and reassemble an rtsp :

  


  rtsp://192.168.1.57:8555/unicast

rtp://192.168.1.77:12348


  


  I have tried this way but it gives me an error :

  


  ffmpeg \
    -i rtsp://192.168.1.57:8555/unicast \
    -i rtp://192.168.1.37:12348 \
    -acodec copy -vcodec libx264 \
    -f rtp_mpegts "rtp://192.168.1.77:5000?ttl=2"


  


  Error :

  


  [h264 @ 0x55ac6acaf4c0] non-existing PPS 0 referenced
    Last message repeated 1 times
[h264 @ 0x55ac6acaf4c0] decode_slice_header error
[h264 @ 0x55ac6acaf4c0] no frame!
[h264 @ 0x55ac6acaf4c0] non-existing PPS 0 referenced
    Last message repeated 1 times
[h264 @ 0x55ac6acaf4c0] decode_slice_header error
[h264 @ 0x55ac6acaf4c0] no frame!
[h264 @ 0x55ac6acaf4c0] non-existing PPS 0 referenced
    Last message repeated 1 times


  


  What am I doing wrong ?