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• FFmpeg reverse long audio hang randomly in Android

  23 mars 2021, par Michael

  I am writing an Android APP, underneath I simply use FFmpeg command to reverse the audio.

  


  The command is simple like :ffmpeg -loglevel debug -debug_ts -i /sdcard/.m4a -af areverse /sdcard/longaudio.aac

  


  If the audio is short, everything works fine, but if the audio longer than 10 mins, the thread will hang(sleep) randomly at some places. The log shows input processing stop in middle at some pkt_pts, every time stop at different ptk_pts. The whole app will therefore hang in there.

  


  If I simply do conversion "ffmpeg -loglevel debug -debug_ts -i /sdcard/.m4a -codec:a aac /sdcard/longaudio.aac" it will work.

  


  Some debug steps I did :

  


  


  1. The memory and cpu usage is normal, it seems the ffmpeg just suddenly decide to take a rest during reverse the long audio :(

     


  


  2. the IO shouldn't be fulled, I commented out the logs still not ok.

     


  


  3. I see a lot "cur_dts is invalid (this is harmless if it occurs once at the start per stream)", but it also showed in normal cases.

     


  


  


  I know the description is kind of ambiguous, but I am so desperate. Anything I don't know about the audio reverse is welcome.

  


• Intermittent video hang-up when recording rtsp stream using

  8 septembre 2020, par DurOhan

  I write a rtsp stream with ffmpeg to raspberry pi. When recording for a long time, it starts to hang from one second to 20 seconds. I used ffmpeg version 4.2.2 for the recording. I noticed this problem on raspberry pi models 2, 3 and 4 but when writing to my computer this problem was not noticed. The command to write ffmpeg :

  


  ffmpeg -rtsp_transport tcp -stimeout 3000000 -i rtsp://192.168.1.10:554/user=admin\&password=\&channel=1\&stream=0.sdp? -hide_banner  -y -vcodec copy -f segment -segment_time 300 -segment_start_number 1 -segment_format mp4 -reset_timestamps 1 -flush_packets 1 /media/CD/TV_%d.mp4 -fflags +genpts -vsync 0 -enc_time_base -1

  


  How can this problem be solved ?

  


• getting frames from rtsp stream ffmpeg — hang in av_read_play

  16 mai 2020, par Stepan Yakovenko

  I'm trying to use this code to get video frames from RTSP stream :

  



  // Open the initial context variables that are needed
SwsContext *img_convert_ctx;
AVFormatContext* format_ctx = avformat_alloc_context();
AVCodecContext* codec_ctx = NULL;
int video_stream_index;
// Register everything
av_register_all();
avformat_network_init();
if (avformat_open_input(&format_ctx, argv[1],
                        NULL, NULL) != 0) {
    return EXIT_FAILURE;
}
if (avformat_find_stream_info(format_ctx, NULL) < 0) {
    return EXIT_FAILURE;
}
//search video stream
for (int i = 0; i < format_ctx->nb_streams; i++) {
    if (format_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
        video_stream_index = i;
}

AVPacket packet;
av_init_packet(&packet);

//open output file
AVFormatContext* output_ctx = avformat_alloc_context();
AVStream* stream = NULL;

//start reading packets from stream and write them to file
av_read_play(format_ctx);    // <-- program is frozen in this API call

// Get the codec
AVCodec *codec = NULL;
cout << "avcodec_find_decoder" < avcodec_find_decoder(AV_CODEC_ID_H264);

// some more important stuff below ...


  



  When I launch my program with MP4 file, it works correctly. If I use it with RTSP H264 stream it doesn't go blow av_read_play. Original ffmpeg binary works correctly with RTSP stream also. What may be the reason for this ?