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• Trying to concatenate 11 seconds of black video onto the end of a 5 min video. Getting non-monotonous DTS in output stream error

  14 janvier 2020, par TidusWulf

  I have a video shot from my smartphone that is 3840x2160@57.74. Originally, it was exactly 5 minutes long. I replaced the audio with a music file that is 5 minutes and 11 seconds using ffmpeg -i video.mp4 -i audio.mp3 -c copy -map 0:v:0 -map 1:a:0 output.mp4 I expected 11 seconds of black at the end, but instead the video output freezes on the last frame for 11 seconds. There’s definitely something funky going on because when I try to upload to youtube, it only sees the first 5 minutes. The last 10 seconds of audio get dropped.

  I tried making a second black clip with ffmpeg -f lavfi -i color=c=black:s=uhd2160:r=57.74 -t 11 -pix_fmt yuv420p blk2.mp4. When I try to concat the two files with ffmpeg -f concat -safe 0 -i list.txt -c copy teacup6.mp4 I get a huge list of errors such as [mp4 @ 00000166fda994c0] Non-monotonous DTS in output stream 0:0; previous: 27002920, current: 3728954; changing to 27002921. This may result in incorrect timestamps in the output file. for what appears to be about 11 seconds worth of frames, so basically the entire 11 second black clip. When I play it in VLC it goes black, but I suspect it’s not actually processing/playing 11 seconds of good black video because if I click along the track timeline, visual glitches start happening in the canvas.

  Here is what ffmpeg tells me about my inputs and outputs as far as framerate, pixel format, etc.

  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000239e6cb2880] Auto-inserting h264_mp4toannexb bitstream filter
Input #0, concat, from 'list.txt':
 Duration: N/A, start: -0.023021, bitrate: 72244 kb/s
   Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 3840x2160, 71994 kb/s, SAR 1:1 DAR 16:9, 57.74 fps, 59 tbr, 90k tbn, 180k tbc
   Metadata:
     handler_name    : VideoHandle
   Stream #0:1(und): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 250 kb/s
   Metadata:
     handler_name    : SoundHandler
Output #0, mp4, to 'teacup5.mp4':
 Metadata:
   encoder         : Lavf58.35.102
   Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 3840x2160 [SAR 1:1 DAR 16:9], q=2-31, 71994 kb/s, 57.74 fps, 59 tbr, 90k tbn, 90k tbc
   Metadata:
     handler_name    : VideoHandle
   Stream #0:1(und): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 250 kb/s
   Metadata:
     handler_name    : SoundHandler
Stream mapping:
 Stream #0:0 -> #0:0 (copy)
 Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help

  alternatively, I tried to make a black 3840x2160 png file and create an 11 second slideshow. It didn’t turn out any better. I tried a single image for 11 seconds @ 57.74fps, I also tried a looping slideshow of that one image, looping on every single frame, at 57.74 fps. I should note that wether a slideshow or a color generator, the filesize for the 11 seconds of black comes out to about 160KB. Strangely small in my opinion, but I was chalking it up to a good compression algorithm.

  I tried to do this in Da Vinci Resolve 16.1 instead and the video wouldn’t play. I also couldn’t find a way to maintain the same unusual 57.74 framerate with the free version, so it was undesirable anyway. I tried to re-process using Handbrake, but it threw an error. The output of the Handbrake processed video file also gets stuck on the last frame of the video, instead of going to black.

• FFmpeg extracts black image from H264 stream

  8 juin 2022, par massivemoisture

  I have a C# application that receives H264 stream through a socket. I want to continuously get the latest image from that stream.

  


  Here's what I did with FFmpeg 5.0.1, just a rough sample to get ONE latest image, how I start FFmpeg :

  


  var ffmpegInfo = new ProcessStartInfo(FFMPEG_PATH);
ffmpegInfo.RedirectStandardInput = true;
ffmpegInfo.RedirectStandardOutput = true;
ffmpegInfo.RedirectStandardError = true;
ffmpegInfo.UseShellExecute = false;

ffmpegInfo.Arguments = "-i pipe: -f h264 -pix_fmt bgr24 -an -sn pipe:";

ffmpegInfo.UseShellExecute = false;
ffmpegInfo.CreateNoWindow = true;

Process myFFmpeg = new Process();
myFFmpeg.StartInfo = ffmpegInfo;
myFFmpeg.EnableRaisingEvents = true;
myFFmpeg.Start();

var inStream = myFFmpeg.StandardInput.BaseStream;
FileStream baseStream = myFFmpeg.StandardOutput.BaseStream as FileStream;
myFFmpeg.BeginErrorReadLine();


  


  Then I start a new thread to receive the stream through socket :

  


  // inStream is "myFFmpeg.StandardInput.BaseStream" from the code block above
var t = Task.Run(() => ReceiveStream(inStream));


  


  Next I read the output from FFmpeg :

  


  byte[] decoded = new byte[Width * Height * 3];
int numBytesToRead = Width * Height * 3;
int numBytesRead = 0;

while (numBytesToRead > 0)
{
   int n = baseStream.Read(decoded, 0, decoded.Length);
   Console.WriteLine($"Read {n} bytes");
   if (n == 0)
   {
      break;
   }              
      numBytesRead += n;
      numBytesToRead -= n;
}


  


  Lastly, I use ImageSharp library to save decoded byte array as a jpeg file.

  


  image.Save("test.jpeg", encoder);


  


  However, test.jpeg always comes out as a black image. What did I do wrong ?
Here's the stderr log that I got from ffmpeg :

  


  
  Duration: N/A, bitrate: N/A
  Stream #0:0: Video: h264 (High), yuv420p(tv, smpte170m/bt470bg/smpte170m, progressive), 1080x2256, 25 fps, 25 tbr, 1200k tbn
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Incompatible pixel format 'bgr24' for codec 'libx264', auto-selecting format 'yuv444p'
[libx264 @ 0x11b9068f0] using cpu capabilities: ARMv8 NEON
[libx264 @ 0x11b9068f0] profile High 4:4:4 Predictive, level 5.0, 4:4:4, 8-bit
Output #0, h264, to 'pipe:':
  Metadata:
    encoder         : Lavf59.16.100
  Stream #0:0: Video: h264, yuv444p(tv, smpte170m/bt470bg/smpte170m, progressive), 1080x2256, q=2-31, 25 fps, 25 tbn
    Metadata:
      encoder         : Lavc59.18.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
frame=    1 fps=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   56 fps=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x
frame=   87 fps= 83 q=28.0 size=     370kB time=00:00:01.16 bitrate=2610.6kbits/s speed=1.11x
frame=  118 fps= 75 q=28.0 size=     698kB time=00:00:02.40 bitrate=2381.4kbits/s speed=1.54x
frame=  154 fps= 75 q=28.0 size=    1083kB time=00:00:03.84 bitrate=2311.1kbits/s speed=1.86x
...


  


  Thank you !

  


  Edit : as suggested by @kesh, I have changed h264 to rawvideo, the arguments now are : -i pipe: -f rawvideo -pix_fmt bgr24 -an -sn pipe:

  


  Here's the output of ffmpeg :

  


  Input #0, h264, from 'pipe:':
  Duration: N/A, bitrate: N/A
  Stream #0:0: Video: h264 (High), yuv420p(tv, smpte170m/bt470bg/smpte170m, progressive), 1080x2256, 25 fps, 25 tbr, 1200k tbn
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> rawvideo (native))
// About 9 of these "No accelerated colorspace..." message
[swscaler @ 0x128690000] [swscaler @ 0x1286a0000] No accelerated colorspace conversion found from yuv420p to bgr24.
Output #0, rawvideo, to 'pipe:':
  Metadata:
    encoder         : Lavf59.16.100
  Stream #0:0: Video: rawvideo (BGR[24] / 0x18524742), bgr24(pc, gbr/bt470bg/smpte170m, progressive), 1080x2256, q=2-31, 1461888 kb/s, 25 fps, 25 tbn
    Metadata:
      encoder         : Lavc59.18.100 rawvideo
frame=    1 fps=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x
// FFmpeg outputs no more log after this


  


• ffmpeg Command stop executing in background after the application kill

  26 mars 2018, par Amjad Khan

  FFmpeg Command are executed and that are working well, Implemented on android.

  But I am facing problem when the user kill the application the command which I have executed it is terminated.

  I have created background service, which is running in the background but the command stop in the middle, is there any way to handle it

  Code here

  ffmpeg.execute(command, new ExecuteBinaryResponseHandler() {
  
      @Override
  
      public void onFailure(String s) {
  
          Log.e(TAG, "FAILED with output : " + s);
  
      }
  
  
  
      @Override
  
      public void onSuccess(String s) {
  
          Log.e(TAG, "SUCCESS with output : " + s);
  
      }
  
  
  
      @Override
  
      public void onProgress(String s) {
  
        //This method get stoped
  
      }
  
  
  
      @Override
  
      public void onStart() {
  
  
  
      }
  
  
  
      @Override
  
      public void onFinish() {
  
  
  
      }
  
  });