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• Concatenating Video Files using FFMPEG YUV issue

  3 novembre 2015, par SpoiledTechie.com

  I am concatenating three videos with FFMPEG.

  The 1st and 3rd video of the concatenation were pulled from an AVI file using FFMPEG and converted into MP4.

  Their codec information is below.

  

  The 2nd video in the concatenation is compiled using FFMPEG. I am compiling frames with FFMPEG to create this video.

  Its codec information is below.

  
  As you can see, the videos share the same codec, resolution and frame rate.

  The only thing they don’t share is the Decoded format. One being 4:4:4 and one being 4:2:2

  I think I understand what YUV means from this link, https://msdn.microsoft.com/en-us/library/windows/desktop/dd391027%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396

  When I concatenate these three videos together, using concat demuxer, it works, but when I try to watch the final video, the video shows the first file playing just right, then the 2nd video in the final video shows up BLANK and the third video plays just fine as well.

  So my question is, how do I concat 3 MP4 files, but change what seems to be the decoded format for the 2nd video to 4:2:2. When I compile the frames, I imagine I can change the YUV format, but I don’t know how just yet.

• How to use Windows Media Foundation instead DirectShow Editing Services ?

  3 novembre 2016, par Den

  I am developing a non-linear video editor. I need to have the support timeline, mixing of audio streams, the transitions between videos, etc. These all features are in DirectShow Editing Services, but it is no longer supported in the new versions of Windows. Instead, offer to use Microsoft Media Foundation. Is it possible to implement the same functionality in the MF or is using other SDK ? For example, gstreamer. Maybe someone will recommend SDK for video editing on the basis of MF ?

• How do I redirect the output of SpeechSynthesizer to a Process of ffmpeg

  27 septembre 2020, par TheOneAndOnlyMrX

  I am trying to have a SpeechSynthesizer generate some audio data, pipe it into a Process of FFmpeg, and have FFmpeg save the data to a file (output.wav). Eventually, the audio data will be used for something else, which is why I am using FFmpeg.

  


  using (MemoryStream voiceStream = new MemoryStream())
        using (Process ffmpeg = new Process())
        {
            SpeechSynthesizer synth = new SpeechSynthesizer();

            int samplesPerSecond = 48000;
            int bitsPerSample = 8;
            int channelCount = 2;
            int averageBytesPerSecond = samplesPerSecond * (bitsPerSample / 8) * channelCount;
            int blockalign = (bitsPerSample / 8) * channelCount;
            byte[] formatSpecificData = new byte[0];

            synth.SetOutputToAudioStream(
                voiceStream,
                new System.Speech.AudioFormat.SpeechAudioFormatInfo(
                    System.Speech.AudioFormat.EncodingFormat.Pcm,
                    samplesPerSecond,
                    bitsPerSample,
                    channelCount,
                    averageBytesPerSecond,
                    blockalign,
                    formatSpecificData
                    )
                );

            synth.Speak("Hello there");

            synth.SetOutputToNull();

            ffmpeg.StartInfo = new ProcessStartInfo
            {
                FileName = "ffmpeg",
                Arguments = $"-y -f u8 -ac 2 -ar 48000 -i pipe:0 out.wav",
                UseShellExecute = false,
                RedirectStandardOutput = true,
                RedirectStandardInput = true
            };

            ffmpeg.Start();

            using (Stream ffmpegIn = ffmpeg.StandardInput.BaseStream)
            {
                voiceStream.CopyTo(ffmpegIn);
                
                ffmpegIn.FlushAsync();
            }
        }


  


  When running the program, FFmpeg said that the input stream contains no data, and returns an empty file.
I believe that I do not interface properly with the Process object, however, the problem might also be my incorrect specification of the audio stream, since I do not know much about audio.