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• ffmpeg - pipe metadata about stream

  4 février 2021, par Mike S.

  I'm in process of writing an app which should process live AV stream and do some magic. Well, it should just display some audio levels.

  


  So far, everything works with one exception. The problem is that I'm piping the stream from basically unknown source (it may be whatever) and I can only guess the channel count and the sample rate.

  


  Is there a way how ffmpeg can tell me this ? Right now, I'm using following command to execute ffmpeg :

  


  ffmpeg -loglevel 40 -hide_banner -re -i pipe:0 -vn -f s16le -acodec pcm_s16le
 pipe:3 -progress pipe:4 -f ffmetadata pipe:5


  


  But ffmetadata is empty and progress does not contain any of required info. I've found ffprobe, which could tell me all I need and then I would kill it, but I believe there is a way to achieve the same with just ffmpeg (and without parsing its stdout).

  


  Thank you !

  


• ffmpeg : error reading header pipe:0 : Invalid argument

  25 février 2021, par Дмитрий Бондаренко

  I need microservice (converter audio using streams), but have problem with ffmpeg

  


  my test ffmpeg

  


  package codec

import (
    "bytes"
    "os"
    "os/exec"
    "testing"
)

func Test1(t *testing.T) {
    in, err := os.Open("/mp4-mp3/src.m4a")
    if err != nil {
        t.Fatal(err.Error())
    }
    out, err := os.OpenFile("/mp4-mp3/out.mp3", os.O_RDWR|os.O_CREATE, 0666)
    if err != nil {
        t.Fatal(err.Error())
    }
    cmd := exec.Command(
        "ffmpeg",
        "-f", "m4a",
        "-i", "pipe:0",
        "-f", "mp3",
        "pipe:1")

    cmd.Stdin = in
    cmd.Stdout = out
    stderr := &bytes.Buffer{}
    cmd.Stderr = stderr
    if err := cmd.Run(); err != nil {
        t.Logf(stderr.String())
        t.Fatal(err.Error())
    }

}



  


  At the exit, I have the error invalid argument
i tried different options but the problem didn't change

  


  === RUN   Test1
    codec_test.go:31: ffmpeg version git-2020-08-31-4a11a6f Copyright (c) 2000-2020 the FFmpeg developers
          built with gcc 10.2.1 (GCC) 20200805
          configuration: hide...
          libavutil      56. 58.100 / 56. 58.100
          libavcodec     58.101.101 / 58.101.101
          libavformat    58. 51.101 / 58. 51.101
          libavdevice    58. 11.101 / 58. 11.101
          libavfilter     7. 87.100 /  7. 87.100
          libswscale      5.  8.100 /  5.  8.100
          libswresample   3.  8.100 /  3.  8.100
          libpostproc    55.  8.100 / 55.  8.100
        [mov,mp4,m4a,3gp,3g2,mj2 @ 0000019ccc3acb40] error reading header
        pipe:0: Invalid argument
    codec_test.go:32: exit status 1
--- FAIL: Test1 (0.07s)
FAIL

Process finished with exit code 1


  


  i decided to use cmd, but i have new problem
pipe:0 : Invalid data found when processing input

  


  cat src.m4a | ffmpeg -f m4a -i pipe:0 out.mp3
ffmpeg version git-2020-08-31-4a11a6f Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 10.2.1 (GCC) 20200805
  configuration: hide...
  libavutil      56. 58.100 / 56. 58.100
  libavcodec     58.101.101 / 58.101.101
  libavformat    58. 51.101 / 58. 51.101
  libavdevice    58. 11.101 / 58. 11.101
  libavfilter     7. 87.100 /  7. 87.100
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0000019afa98d800] invalid STSD entries 1
[mov,mp4,m4a,3gp,3g2,mj2 @ 0000019afa98d800] error reading header
pipe:0: Invalid data found when processing input



  


  How to properly set ffmpeg parameters to convert from stream to stream ?

  


• ffmpeg pipe to generate h264 chunks from numpy array or bgr24 bytes

  25 février 2021, par harsh solanki

  is there a possibility if someone can help me with FFmpeg pipe to generate h264 chunks from NumPy array

  


  This is what I am doing now :

  


  process = (
ffmpeg
.input('pipe :', format='rawvideo', pix_fmt='bgr24', s='{}x{}'.format(self._deeptwin.image_width, self._deeptwin.image_height))
.output(path, pix_fmt='yuv420p', vcodec='libx264', r=25)
.overwrite_output()
.run_async(pipe_stdin=True)
)

  


  for res in response:
    st = datetime.datetime.now()
    print(f'{res.status} image {res.id} rendered at {datetime.datetime.now()}')
    img = np.frombuffer(res.image, dtype=np.uint8)
    img = img.reshape((int(self._deeptwin.image_height * 1.5), self._deeptwin.image_width))
    img = cv2.cvtColor(img, cv2.COLOR_YUV2BGR_I420)
    
    for frame in img:
        start = datetime.datetime.now()
        process.stdin.write(
            frame
            .astype(np.uint8)
            .tobytes()
        )
        end = datetime.datetime.now()
    stop = datetime.datetime.now()
    print(f'{res.id} conversion done at {stop-st}')
process.stdin.close()
process.wait()


  


  `
What this is doing currently is generating an out.h264 file. It is fine and playing a correct video as well.

  


  However, what I need to achieve : I want to generate chunks of h264 frames in the following way : 1.h264, 2.h264............n.h264

  


  Any guidance would be really appreciated and helpful.

  


  Thanks in advance.