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• Feed output of one filter to the input of one filter multiple times with ffmpeg

  27 août 2021, par kentcdodds

  I have the following ffmpeg commands to create a podcast episode :

  


  # remove all silence at start and end of the audio files
ffmpeg -i call.mp3 -af silenceremove=1:0:-50dB call1.mp3
ffmpeg -i response.mp3 -af silenceremove=1:0:-50dB response1.mp3

# remove silence longer than 1 second anywhere within the audio files
ffmpeg -i call1.mp3 -af silenceremove=stop_periods=-1:stop_duration=1:stop_threshold=-50dB call2.mp3
ffmpeg -i response1.mp3 -af silenceremove=stop_periods=-1:stop_duration=1:stop_threshold=-50dB response2.mp3

# normalize audio files
ffmpeg -i call2.mp3 -af loudnorm=I=-16:LRA=11:TP=0.0 call3.mp3
ffmpeg -i response2.mp3 -af loudnorm=I=-16:LRA=11:TP=0.0 response3.mp3

# cross fade audio files with intro/interstitial/outro
ffmpeg -i intro.mp3 -i call3.mp3 -i interstitial.mp3 -i response3.mp3 -i outro.mp3
  -filter_complex "[0][1]acrossfade=d=1:c2=nofade[a01];
                   [a01][2]acrossfade=d=1:c1=nofade[a02];
                   [a02][3]acrossfade=d=1:c2=nofade[a03];
                   [a03][4]acrossfade=d=1:c1=nofade"
  output.mp3


  


  While this "works" fine, I can't help but feel like it would be more efficient to do this all in one ffmpeg command. Based on what I found online this should be possible, but I don't understand the syntax well enough to know how to make it work. Here's what I tried :

  


  ffmpeg -i intro.mp3 -i call.mp3 -i interstitial.mp3 -i response.mp3 -i outro.mp3
       -af [1]silenceremove=1:0:-50dB[trimmedCall]
       -af [3]silenceremove=1:0:-50dB[trimmedResponse]
       -af [trimmedCall]silenceremove=stop_periods=-1:stop_duration=1:stop_threshold=-50dB[noSilenceCall]
       -af [trimmedResponse]silenceremove=stop_periods=-1:stop_duration=1:stop_threshold=-50dB[noSilenceResponse]
       -af [noSilenceCall]loudnorm=I=-16:LRA=11:TP=0.0[call]
       -af [noSilenceResponse]loudnorm=I=-16:LRA=11:TP=0.0[response]
      -filter_complex "[0][call]acrossfade=d=1:c2=nofade[a01];
                       [a01][2]acrossfade=d=1:c1=nofade[a02];
                       [a02][response]acrossfade=d=1:c2=nofade[a03];
                       [a03][4]acrossfade=d=1:c1=nofade"
  output.mp3


  


  But I have a feeling I have a fundamental misunderstanding of this because I got this error which I don't understand :

  


  Stream specifier 'call' in filtergraph description 
[0][call]acrossfade=d=1:c2=nofade[a01];
[a01][2]acrossfade=d=1:c1=nofade[a02];
[a02][response]acrossfade=d=1:c2=nofade[a03];
[a03][4]acrossfade=d=1:c1=nofade
       matches no streams.


  


  For added context, I'm running all these commands through @ffmpeg/ffmpeg so that last command actually looks like this (in JavaScript) :

  


  await ffmpeg.run(
  '-i', 'intro.mp3',
  '-i', 'call.mp3',
  '-i', 'interstitial.mp3',
  '-i', 'response.mp3',
  '-i', 'outro.mp3',
  '-af', '[1]silenceremove=1:0:-50dB[trimmedCall]',
  '-af', '[3]silenceremove=1:0:-50dB[trimmedResponse]',
  '-af', '[trimmedCall]silenceremove=stop_periods=-1:stop_duration=1:stop_threshold=-50dB[noSilenceCall]',
  '-af', '[trimmedResponse]silenceremove=stop_periods=-1:stop_duration=1:stop_threshold=-50dB[noSilenceResponse]',
  '-af', '[noSilenceCall]loudnorm=I=-16:LRA=11:TP=0.0[call]',
  '-af', '[noSilenceResponse]loudnorm=I=-16:LRA=11:TP=0.0[response]',
  '-filter_complex', `
[0][call]acrossfade=d=1:c2=nofade[a01];
[a01][2]acrossfade=d=1:c1=nofade[a02];
[a02][response]acrossfade=d=1:c2=nofade[a03];
[a03][4]acrossfade=d=1:c1=nofade
  `,
  'output.mp3',
)


  


• How can I stream very long H.264 videos over HTTP without long startup times ? (or : MOOV atom too large)

  5 octobre 2012, par michael

  I want to stream videos of public meetings that are often 10 hours long. Users will generally be starting at some point in the middle of the video and jumping around frequently.

  H.264 in an MP4 container seems like the current best option for encoding streaming video (right ?). But these are large files — about 1.3GB for one file — and the metadata (MOOV atom) at the beginning of the file is itself about 40MB. If I understand correctly, clients need to download the full metadata before they're able to seek within the remainder of the file. Obviously, having to download 40MB before you can start streaming is unacceptable.

  (My tests of streaming have been with VLC and the HTML5 tag in Chrome.)

  I'm encoding the file using avconv, and am currently providing no additional settings beyond telling it which encoders to use (x264 and libfaac). I then move the metadata to the beginning of the file using qt-faststart.

  Is there a way to make the MOOV atom smaller ?

  If not, are there other strategies to use (e.g. is splitting long videos into several files something that's frequently done ? it seems like a real pain in terms of users seeking around the whole day's video) ?

  Or should I be using a different codec or container ?

  thanks !

  Here's a breakdown of the file header structure, from AtomicParsley :

  Atom ftyp @ 0 of size: 32, ends @ 32
  
  Atom moov @ 32 of size: 40157673, ends @ 40157705
  
       Atom mvhd @ 40 of size: 108, ends @ 148
  
       Atom iods @ 148 of size: 24, ends @ 172
  
       Atom trak @ 172 of size: 20156304, ends @ 20156476
  
           Atom tkhd @ 180 of size: 92, ends @ 272
  
           Atom edts @ 272 of size: 36, ends @ 308
  
               Atom elst @ 280 of size: 28, ends @ 308
  
           Atom mdia @ 308 of size: 20156168, ends @ 20156476
  
               Atom mdhd @ 316 of size: 32, ends @ 348
  
               Atom hdlr @ 348 of size: 45, ends @ 393
  
               Atom minf @ 393 of size: 20156083, ends @ 20156476
  
                   Atom vmhd @ 401 of size: 20, ends @ 421
  
                   Atom dinf @ 421 of size: 36, ends @ 457
  
                       Atom dref @ 429 of size: 28, ends @ 457
  
                   Atom stbl @ 457 of size: 20156019, ends @ 20156476
  
                       Atom stsd @ 465 of size: 147, ends @ 612
  
                           Atom avc1 @ 481 of size: 131, ends @ 612
  
                               Atom avcC @ 567 of size: 45, ends @ 612
  
                       Atom stts @ 612 of size: 6115608, ends @ 6116220
  
                       Atom stss @ 6116220 of size: 16960, ends @ 6133180
  
                       Atom ctts @ 6133180 of size: 5683824, ends @ 11817004
  
                       Atom stsc @ 11817004 of size: 28, ends @ 11817032
  
                       Atom stsz @ 11817032 of size: 4169724, ends @ 15986756
  
                       Atom stco @ 15986756 of size: 4169720, ends @ 20156476
  
       Atom trak @ 20156476 of size: 20001133, ends @ 40157609
  
           Atom tkhd @ 20156484 of size: 92, ends @ 20156576
  
           Atom mdia @ 20156576 of size: 20001033, ends @ 40157609
  
               Atom mdhd @ 20156584 of size: 32, ends @ 20156616
  
               Atom hdlr @ 20156616 of size: 45, ends @ 20156661
  
               Atom minf @ 20156661 of size: 20000948, ends @ 40157609
  
                   Atom smhd @ 20156669 of size: 16, ends @ 20156685
  
                   Atom dinf @ 20156685 of size: 36, ends @ 20156721
  
                       Atom dref @ 20156693 of size: 28, ends @ 20156721
  
                   Atom stbl @ 20156721 of size: 20000888, ends @ 40157609
  
                       Atom stsd @ 20156729 of size: 96, ends @ 20156825
  
                           Atom mp4a @ 20156745 of size: 80, ends @ 20156825
  
                               Atom esds @ 20156781 of size: 44, ends @ 20156825
  
                       Atom stts @ 20156825 of size: 9348168, ends @ 29504993
  
                       Atom stsc @ 29504993 of size: 28, ends @ 29505021
  
                       Atom stsz @ 29505021 of size: 5326296, ends @ 34831317
  
                       Atom stco @ 34831317 of size: 5326292, ends @ 40157609
  
       Atom udta @ 40157609 of size: 96, ends @ 40157705
  
           Atom meta @ 40157617 of size: 88, ends @ 40157705
  
               Atom hdlr @ 40157629 of size: 33, ends @ 40157662
  
               Atom ilst @ 40157662 of size: 43, ends @ 40157705
  
                   Atom ©too @ 40157670 of size: 35, ends @ 40157705
  
                       Atom data @ 40157678 of size: 27, ends @ 40157705
  
  Atom free @ 40157705 of size: 8, ends @ 40157713
  
  Atom mdat @ 40157713 of size: 1320096566, ends @ 1360254279

• I'm trying to merge videos using fluent-ffmpeg, but some times it merges videos , but whenever we tries to merge videos second time it shows error

  9 janvier 2024, par Asif Mujawar

  const express =require('express')
const app = express()
const ffmpeg = require('fluent-ffmpeg')
const ffmpegPath = require('@ffmpeg-installer/ffmpeg')
const ffprobe = require('@ffprobe-installer/ffprobe')

const first = './videos/first.mp4'
const second = './videos/second.mp4'
const third = './videos/third.mp4'
const fourth = './videos/fourth.mp4'

ffmpeg.setFfprobePath(ffprobe.path)
ffmpeg.setFfmpegPath(ffmpegPath.path)

app.use(express.json())

app.use("/",(req,res)=>{
    res.send("hello")

    ffmpeg()
    .input(first)
    .input(second)
 
    .on('end', function() {
      console.log('files have been merged succesfully');
    })
    .on('error', function(err) {
      console.log('an error happened: ' + err.message);
    })
    .mergeToFile("final.mp4")
  })
  

app.listen(8800,()=>{
    console.log("backend is running 8800")
})



  


  but it shows error whenever we try to merge videos second time

  


  an error happened : ffmpeg exited with code 1 : Cannot find a matching stream for unlabeled input pad 3 on filter Parsed_concat_0

  


  an error happened : ffmpeg exited with code 1 : Cannot find a matching stream for unlabeled input pad 3 on filter Parsed_concat_0