Newest 'ffmpeg' Questions - Stack Overflow

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• How to add audio to specific time [ffmpeg]

  20 mai 2019, par EJL

  So far, I've manage to add audio to the video in ffmpeg but it is playing all along. The enable='between(t,start,end)' option is not working

  I have tried googling for possible answers but my approach is different. I wanted to enable/disable the audio repeatedly in the video.

  SO far I have this code:

  ffmpeg -y -i cut.mp4 -i typing.mp3 -filter_complex "[0:v]drawtext=enable='between(t,0,3)':fontfile=fonts/RobotoBoldCondensed.ttf:text='Finding Nemo...':fontcolor=white:fontsize=24:x=50:y=h-h/5+20[v0]; [1:a]volume=enable='between(t,0,3)'[a3]" -vcodec libx264 -c:a libfdk_aac -map "[v0]" -map "[a3]" -preset ultrafast -async 1  output.mp4
  

• ffmpeg feeding mp4 file to rtsp stream

  20 mai 2019, par damini chopra

  I am trying to feed a mp4 file from ffmpeg to rtsp stream using the command on centos 7:

  from console 1: ffmpeg -i space.mp4 -vcodec libx264 -tune zerolatency -crf 18 http://localhost:8050/feed1.ffm

  from console 2: I have started ffserver and it is started listening.

  But when i open http://x.x.x.x:8050/feed1.ffm in browser it shows error:

  File ??feed1.ffm? not found

  My ffserver.conf file is attached

  Pls help?enter link description here

• How can I separate audio channels using libav C API ?

  20 mai 2019, par zhenghong li

  I have some stereo audio files, and I wanna separate the left channel from the right channel and output the two channels into two different files/streams/containers using libav C API, how can I do that? The libav API documentation is good, but it takes time to read and try all these functions. Could anyone please give me a specific example.

• Dynamic/Moving crop on cameraview on Android ? [on hold]

  20 mai 2019, par Suisse

  I use MLkit to get the position and bounding box size of the persons head in the cameraview, what is the next step to crop the video frame by frame?

• Problems piping ffmpeg to flac encoder

  19 mai 2019, par Sebastian Olsen

  I need to encode a flac file with seektables, ffmpeg's flac encoder does not include seektables, so I need to use the flac CLI. I'm trying to make it possible to convert any arbitrary audio file to a seekable flac file by first piping it through ffmpeg, then to the flac encoder.

  export const transcodeToFlac: AudioTranscoder<{}> = ({
    source,
    destination
  }) => {
    return new Promise((resolve, reject) => {
      let totalSize = 0
  
      const { stdout: ffmpegOutput, stderr: ffmpegError } = spawn("ffmpeg", [
        "-i",
        source,
        "-f",
        "wav",
        "pipe:1"
      ])
  
      const { stdout: flacOutput, stdin: flacInput, stderr: flacError } = spawn(
        "flac",
        ["-"]
      )
  
      flacOutput.on("data", (buffer: Buffer) => {
        totalSize += buffer.byteLength
      })
  
      ffmpegError.on("data", error => {
        console.log(error.toString())
      })
  
      flacError.on("data", error => {
        console.log(error.toString())
      })
  
      //stream.on("error", reject)
  
      destination.on("finish", () => {
        resolve({
          mime: "audio/flac",
          size: totalSize,
          codec: "flac",
          bitdepth: 16,
          ext: "flac"
        })
      })
  
      ffmpegOutput.pipe(flacInput)
      flacOutput.pipe(destination)
    })
  }
  

  While this code works, the resulting flac file is not correct. The source audio is of duration 06:14, but the flac file is of duration 06:45:47. Encoding the flac manually without piping ffmpeg to it works fine, but I cannot do that in a server environment where I need to utilize streams.

  Here's what the flac encoder outputs when transcoding:

  flac 1.3.2
  Copyright (C) 2000-2009  Josh Coalson, 2011-2016  Xiph.Org Foundation
  flac comes with ABSOLUTELY NO WARRANTY.  This is free software, and you are
  welcome to redistribute it under certain conditions.  Type `flac' for details.
  
  -: WARNING: skipping unknown chunk 'LIST' (use --keep-foreign-metadata to keep)
  -: WARNING, cannot write back seekpoints when encoding to stdout
  -: 0% complete, ratio=0.357
  0% complete, ratio=0.432
  0% complete, ratio=0.482
  0% complete, ratio=0.527
  0% complete, ratio=0.541
  1% complete, ratio=0.554
  1% complete, ratio=0.563
  1% complete, ratio=0.571
  size=   36297kB time=00:03:30.70 bitrate=1411.2kbits/s speed= 421x
  1% complete, ratio=0.572
  1% complete, ratio=0.570
  1% complete, ratio=0.577
  1% complete, ratio=0.583
  1% complete, ratio=0.584
  1% complete, ratio=0.590
  1% complete, ratio=0.592
  size=   64512kB time=00:06:14.49 bitrate=1411.2kbits/s speed= 421x
  video:0kB audio:64512kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead:
  0.000185%
  
  -: WARNING: unexpected EOF; expected 1073741823 samples, got 16510976 samples
  2% complete, ratio=0.579