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• How to capture ffmpeg output in rails ?

  18 août 2019, par HelloWorld

  I’m running a ffmpeg command to try to get the duration of a video file, the command is as follows...

  system('ffmpeg -i C:\Users\example\Desktop\video9.mp4 -f ffmetadata')

  When I run that line it outputs a lot of info to the rails console, including duration. But how would I capture that info so I can split it and grab the data I need ? (I’m doing this inside a rails controller)

  When I run something like this...

  metadata = system('ffmpeg -i C:\Users\example\Desktop\video9.mp4 -f ffmetadata')
  
  puts metadata

  All it returns is false.

• Why doesn't the ffmpeg output display the stream in the browser ? [closed]

  10 mai 2024, par Tebyy

  Why is it that when I create a livestream in Python using ffmpeg, and then I open the browser and visit the page, the page keeps loading continuously, and in PyCharm logs, I see binary data ? There are no errors displayed, and the code seems correct to me. I even tried saving to a file for testing purposes, and when I play the video, everything works fine. Does anyone know what might be wrong here ?

  


  Code :

  


  def generate_frames():
    cap = cv2.VideoCapture(os.path.normpath(app_root_dir().joinpath("data/temp", "video-979257305707693982.mp4")))
    while cap.isOpened():
        ret, frame = cap.read()
        if not ret:
            break

        yield frame


@app.route('/video_feed')
def video_feed():
    ffmpeg_command = [
        'ffmpeg', '-f', 'rawvideo', '-pix_fmt', 'bgr24',
        '-s:v', '1920x1080', '-r', '60',
        '-i', '-', '-vf', 'setpts=2.5*PTS', # Video Speed
        '-c:v', 'libvpx-vp9', '-g', '60', '-keyint_min', '60',
        '-b:v', '6M', '-minrate', '4M', '-maxrate', '12M', '-bufsize', '8M',
        '-crf', '0', '-deadline', 'realtime', '-tune', 'psnr', '-quality', 'good',
        '-tile-columns', '6', '-threads', '8', '-lag-in-frames', '16',
        '-f', 'webm', '-'
    ]
    ffmpeg_process = subprocess.Popen(ffmpeg_command, stdin=subprocess.PIPE, stderr=subprocess.PIPE, bufsize=-1)
    frames_generator = generate_frames()
    for frame in frames_generator:
        ffmpeg_process.stdin.write(frame)
        ffmpeg_process.stdin.flush()

    ffmpeg_process.stdin.close()
    ffmpeg_process.wait()

    def generate_video_stream(process):
        startTime = time.time()
        buffer = []
        sentBurst = False
        for chunk in iter(lambda: process.stderr.read(4096), b''):
            buffer.append(chunk)

            # Minimum buffer time, 3 seconds
            if sentBurst is False and time.time() > startTime + 3 and len(buffer) > 0:
                sentBurst = True
                for i in range(0, len(buffer) - 2):
                    print("Send initial burst #", i)
                    yield buffer.pop(0)

            elif time.time() > startTime + 3 and len(buffer) > 0:
                yield buffer.pop(0)

            process.poll()
            if isinstance(process.returncode, int):
                if process.returncode > 0:
                    print('FFmpeg Error', process.returncode)

                break

    return Response(stream_with_context(generate_video_stream(ffmpeg_process)), mimetype='video/webm', content_type="video/webm; codecs=vp9", headers=Headers([("Connection", "close")]))



  


• FFMPeg generated video : Audio has 'glitches' when uploaded to YouTube

  7 octobre 2023, par CularBytes

  I've generated a voice from Azure AI Speech at 48KHz and 96K Bit Rate, generated a video of some stock footages and I'm trying to combine all of that with a background music.
The voice-over is generated per setence, so that I know how long each setence is and to include relevant video footage.

  


  I'm using FFMpeg through the FFMpegCore nuget package.

  


  The problem

  


  After the video is complete with background music, I play it on my computer and it's perfect (no audio glitches, music keeps playing). But when uploaded to youtube it has 'breaks' in the music inbetween sentences (basically everytime a new voice-fragment is starting).

  


  Example : https://www.youtube.com/watch?v=ieNvQ2TNq44

  


  The code

  


  All of the footage is combined with mostly FFMpeg.Join(string output, string[] videos). These video files also contain the voice-overs (per sentance).

  


  After that I try to add the music like this :

  


     string outputTimelineWithMusicPath = _workingDir + $@"\{videoTitle}_withmusic.mp4";
    FFMpegArguments
        .FromFileInput(inputVideoPath)
        .AddFileInput(musicPath)
        .OutputToFile(outputPath, true, options => options
            .CopyChannel()
            .WithAudioCodec(AudioCodec.Aac)
            .WithAudioBitrate(AudioQuality.Good)
            .UsingShortest(true)
            .WithCustomArgument("-filter_complex \"[0:a]aformat=fltp:44100:stereo,apad[0a];[1]aformat=fltp:44100:stereo,volume=0.05[1a];[0a][1a]amerge[a]\" -map 0:v -map \"[a]\" -ac 2"))
        .ProcessSynchronously();


  


  I've tried to mess around with the CustomArgument, but so far no success.

  


  For example, I thought removing apad from the argument so no 'blank spots' are added, should perhaps fix the issue. Also tried to use amix instead of amerge.

  


  Last try

  


  I've tried to first make sure both files had the same sample rate, in the hope to fix the issue. So far, no success

  


      string outputVideoVoicePath = _workingDir + $@"\{title}_voiceonly_formatting.mp4";
    string musicReplacePath = _workingDir + $@"\{title}_music_formatted.aac";
    FFMpegArguments
    .FromFileInput(inputVideoPath)
    .OutputToFile(outputVideoVoicePath, true, options => options
        .WithAudioCodec(AudioCodec.Aac)
        .WithAudioBitrate(128)
        .WithAudioSamplingRate(44100)
    )
    .ProcessSynchronously();
    
    FFMpegArguments
        .FromFileInput(music.FilePath)
        .OutputToFile(musicReplacePath, true, options => options
            .WithAudioCodec(AudioCodec.Aac)
            .WithAudioBitrate(256) //also tried 96 (which is original format)
            .WithAudioSamplingRate(44100)
        )
        .ProcessSynchronously();
    
    
    Console.WriteLine("Add music...");
    var videoTitle = Regex.Replace(title, "[^a-zA-Z]+", "");
    string outputTimelineWithMusicPath = _workingDir + $@"\{videoTitle}_withmusic.mp4";
    FFMpegArguments
        .FromFileInput(outputVideoVoicePath)
        .AddFileInput(musicReplacePath)
        .OutputToFile(outputTimelineWithMusicPath, true, options => options
            .CopyChannel()
            .WithAudioCodec(AudioCodec.Aac)
            .WithAudioBitrate(AudioQuality.Good)
            .UsingShortest(true)
            .WithCustomArgument("-filter_complex \"[0:a]aformat=fltp:44100:stereo[0a];[1]aformat=fltp:44100:stereo,volume=0.05[1a];[0a][1a]amix=inputs=2[a]\" -map 0:v -map \"[a]\" -ac 2"))
        .ProcessSynchronously();
    return outputTimelineWithMusicPath;


  


  I'm not much of an expert when it comes to audio/video codecs. I do scale each stock video to 24fps, 1920x1080 and the music has a original bitrate of 256Kbps / 44100 sample rate (so I probably don't even have to convert the audio file).