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• FFmpeg : merge 8 mono audio streams MOV file into one audio stream FLV file

  1er décembre 2015, par snucky

  I have a MOV file with eight mono audio streams, likely a 5.1 or 7.1 setup. I want to generate a for-web preview FLV file from it but in doing so lose the voices in the dialogue. FFmpeg is likely favoring an audio stream out of the eight that doesn’t have the voices. When I researched ways to merge the audio streams, in order to bring the voices back, I lose the ability to execute my ffmpeg command entirely. Here’s what I have at the moment (the introduction of the "-map 0" option rendered the command non-executable)

  /usr/local/bin/ffmpeg -i ../vmx_files/6711177.mov -map 0 -y -f flv -qmax 10
  
        -vf "scale=trunc(oh*a/2)*2:720" -ar 44100 -ab 64k assets/flv/6711177.flv
  
  
  
  
  
  ffmpeg version N-69160-g1013c15 Copyright (c) 2000-2015 the FFmpeg developers
  
    built on Jan 20 2015 09:41:10 with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-11)
  
    configuration:
  
    libavutil      54. 17.100 / 54. 17.100
  
    libavcodec     56. 20.100 / 56. 20.100
  
    libavformat    56. 19.100 / 56. 19.100
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5.  8.100 /  5.  8.100
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '../vmx_files/6711177.mov':
  
    Metadata:
  
      major_brand     : qt
  
      minor_version   : 537199360
  
      compatible_brands: qt
  
      creation_time   : 2015-11-24 23:00:27
  
    Duration: 00:01:48.34, start: 0.000000, bitrate: 229443 kb/s
  
      Stream #0:0(eng): Video: prores (apch / 0x68637061), yuv422p10le(bt709), 1920x1080, 220043 kb/s, SAR 1:1 DAR 16:9, 29.97 fps, 29.97 tbr, 2997 tbn, 2997 tbc (default)
  
      Metadata:
  
        creation_time   : 2015-11-24 23:00:27
  
        handler_name    : Apple Alias Data Handler
  
        encoder         : Apple ProRes 422 (HQ)
  
        timecode        : 00:59:50;00
  
      Stream #0:1(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32 (24 bit), 1152 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-11-24 23:00:27
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:2(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32 (24 bit), 1152 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-11-24 23:00:27
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:3(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32 (24 bit), 1152 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-11-24 23:00:27
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:4(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32 (24 bit), 1152 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-11-24 23:00:27
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:5(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32 (24 bit), 1152 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-11-24 23:00:27
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:6(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32 (24 bit), 1152 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-11-24 23:00:27
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:7(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32 (24 bit), 1152 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-11-24 23:00:27
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:8(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32 (24 bit), 1152 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-11-24 23:00:28
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:9(eng): Data: none (tmcd / 0x64636D74)
  
      Metadata:
  
        rotate          : -0
  
        creation_time   : 2015-11-24 23:03:22
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:59:50;00
  
  Data stream encoding not supported yet (only streamcopy)

• How to print Continuous output of Popen when reset character is used

  25 août 2022, par cclloyd

  I have a snippet of code that runs a video conversion using ffmpeg.

  


  I read the output to analyze it later in the application, and also want to print it to console, for user feedback.

  


  So I have

  


  p = Popen(['ffmpeg', *args], stderr=STDOUT, stdout=PIPE)
while True:
    line = p.stdout.readline()
    if not line: 
        break
    print(line.decode('utf-8'), end='')

p.wait()
if p.returncode == 0:
    pass



  


  Which works, somewhat. It prints the initial output of the ffmpeg command, as those are simple print statements.

  


  But once the conversion starts, all the output is updated on one line, presumably using some reset character to move the cursor position back to the start of the line.

  


  Is there a way to continue to print that output ?

  


  Edit :

  


  Answer

  


  p = subprocess.Popen(args, stderr=subprocess.STDOUT, stdout=subprocess.PIPE, universal_newlines=True)

with p.stdout:
    for line in iter(p.stdout.readline, None):
        if not line:
            break
        if line.startswith('frame'):
            print(f'\033[2K{line.strip()}\r', end='')
        else:
            print(line, end='')


  


  This includes the cursor return, and clears the current line before printing to it again. And still prints the part I want on the same line, like it normally does.

  


• How to get video stream information with RtspClientSharp library ?

  13 septembre 2022, par theateist

  I use RtspClientSharp to receive video frames from rtsp stream. The library allows just to receive the frames. But, I need to get information about the stream, such as bitrate, codec and etc. I don't see that there is currently an option for this in the library.

  


  

  1. Do I miss something or I need to modify the RtspClientSharp code to support this ?

  


  2. Other alternative is to write a helper code in c++ which uses ffmpeg. I can use pinvoke to call c++ code which will connect to the rtsp stream (in addition to RtspClientSharp client), get the stream information and send it back to my c# code. Is this a better alternative ?