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• 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

• ffmpeg : Cannot find a matching stream for unlabeled input pad 0 on filter Parsed_pad_5

  26 mars 2019, par rsswtmr

  This shouldn’t be that hard. I’m trying to combine three disparate video sources. I’m upscaling them to a consistent 1280x720 frame, with black backgrounds for letterboxing, and trying to concatenate to the output file. The two input files are show segments, and the bumper is a random commercial that goes in the middle.

  On an iMac Pro, System 10.14.3, ffmpeg 4.1.1. The command I’m trying to make work is :

  ffmpeg -y -hide_banner -i "input1.mkv" -i "bumper.mkv" -i "input2.mkv" -filter_complex '[0:v]scale=1280x720:force_original_aspect_ratio=increase[v0],pad=1280x720:max(0\,(ow-iw)/2):max(0\,(oh-ih)/2):black[v0]; [1:v]scale=1280x720:force_original_aspect_ratio=increase[v1],pad=1280x720:max(0\,(ow-iw)/2):max(0\,(oh-ih)/2):black[v1]; [2:v]scale=1280x720:force_original_aspect_ratio=increase[v2],pad=1280x720:max(0\,(ow-iw)/2):max(0\,(oh-ih)/2):black[v2]; [v0][0:a][v1][1:a][v2][2:a]concat=n=3:v=1:a=1 [outv] [outa]' -map "[outv]" -map "[outa]" 'output.mkv'

  The resulting frame I get back is :

  [h264 @ 0x7fbec9000600] [verbose] Reinit context to 720x480, pix_fmt: yuv420p
  
  [info] Input #0, matroska,webm, from 'input1.mkv':
  
  [info]   Metadata:
  
  [info]     encoder         : libebml v0.7.7 + libmatroska v0.8.1
  
  [info]     creation_time   : 2009-07-20T01:33:54.000000Z
  
  [info]   Duration: 00:12:00.89, start: 0.000000, bitrate: 1323 kb/s
  
  [info]     Stream #0:0(eng): Video: h264 (High), 1 reference frame, yuv420p(progressive, left), 708x480 (720x480) [SAR 10:11 DAR 59:44], 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
  
  [info]     Stream #0:1(eng): Audio: ac3, 48000 Hz, stereo, fltp, 160 kb/s (default)
  
  [info]     Metadata:
  
  [info]       title           : English AC3
  
  [info]     Stream #0:2(eng): Subtitle: subrip
  
  [h264 @ 0x7fbec9019a00] [verbose] Reinit context to 304x240, pix_fmt: yuv420p
  
  [info] Input #1, matroska,webm, from 'bumper.mkv':
  
  [info]   Metadata:
  
  [info]     CREATION_TIME   : 2019-03-15T15:16:00Z
  
  [info]     ENCODER         : Lavf57.7.2
  
  [info]   Duration: 00:00:18.18, start: 0.000000, bitrate: 274 kb/s
  
  [info]     Stream #1:0: Video: h264 (Main), 1 reference frame, yuv420p(tv, smpte170m/smpte170m/bt709, progressive, left), 302x232 (304x240) [SAR 1:1 DAR 151:116], 29.97 fps, 29.97 tbr, 1k tbn, 180k tbc (default)
  
  [info]     Stream #1:1: Audio: aac (LC), 44100 Hz, stereo, fltp, delay 2111 (default)
  
  [info]     Metadata:
  
  [info]       title           : Stereo
  
  [error] Truncating packet of size 3515 to 1529
  
  [h264 @ 0x7fbec9014600] [verbose] Reinit context to 704x480, pix_fmt: yuv420p
  
  [h264 @ 0x7fbec9014600] [info] concealing 769 DC, 769 AC, 769 MV errors in I frame
  
  [matroska,webm @ 0x7fbec9011e00] [error] Read error at pos. 50829 (0xc68d)
  
  [info] Input #2, matroska,webm, from 'input2.mkv':
  
  [info]   Metadata:
  
  [info]     encoder         : libebml v0.7.7 + libmatroska v0.8.1
  
  [info]     creation_time   : 2009-07-19T22:37:48.000000Z
  
  [info]   Duration: 00:10:07.20, start: 0.000000, bitrate: 1391 kb/s
  
  [info]     Stream #2:0(eng): Video: h264 (High), 1 reference frame, yuv420p(progressive, left), 704x480 [SAR 10:11 DAR 4:3], 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
  
  [info]     Stream #2:1(eng): Audio: ac3, 48000 Hz, stereo, fltp, 160 kb/s (default)
  
  [info]     Metadata:
  
  [info]       title           : English AC3
  
  [info]     Stream #2:2(eng): Subtitle: subrip
  
  [Parsed_scale_0 @ 0x7fbec8716540] [verbose] w:1280 h:720 flags:'bilinear' interl:0
  
  [Parsed_scale_2 @ 0x7fbec8702480] [verbose] w:1280 h:720 flags:'bilinear' interl:0
  
  [Parsed_scale_4 @ 0x7fbec8702e40] [verbose] w:1280 h:720 flags:'bilinear' interl:0
  
  [fatal] Cannot find a matching stream for unlabeled input pad 0 on filter Parsed_pad_5
  
  [AVIOContext @ 0x7fbec862bfc0] [verbose] Statistics: 104366 bytes read, 2 seeks
  
  [AVIOContext @ 0x7fbec870a100] [verbose] Statistics: 32768 bytes read, 0 seeks
  
  [AVIOContext @ 0x7fbec87135c0] [verbose] Statistics: 460284 bytes read, 2 seeks

  I have no idea what Parsed_pad_5 means. I Googled Cannot find a matching stream for unlabeled input pad and found absolutely no explanation, anywhere. I’m a relative ffmpeg newbie. Before I start rooting around in the source code, can anyone point me in the right direction ? Thanks in advance.

• Using FFMPEG to reliably convert videos to mp4 for iphone/ipod and flash players

  13 janvier 2023, par Jake Stevenson

  I need to convert videos for use in both a flash player and the iphone/ipod touch. I'm using the following batch script with ffmpeg :

  



  @echo off
ffmpeg.exe -i %1 -s qvga -acodec libfaac -ar 22050 -ab 128k -vcodec libx264 -threads 0 -f ipod %2


  



  This always outputs an mp4 file, and I can always play it on my PC. The videos also seem to play fine on my iphone 3GS. But with some input files it won't work for older iphone versions (3G and iPod touch).

  



  Here's the ffmpeg output from one such file :

  



  D:\ffmpeg>encode.bat d:\temp\recording.flv d:\temp\out.m4v
FFmpeg version SVN-r18709, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --enable-memalign-hack --prefix=/mingw --cross-prefix=i686-ming
w32- --cc=ccache-i686-mingw32-gcc --target-os=mingw32 --arch=i686 --cpu=i686 --e
nable-avisynth --enable-gpl --enable-zlib --enable-bzlib --enable-libgsm --enabl
e-libfaac --enable-libfaad --enable-pthreads --enable-libvorbis --enable-libtheo
ra --enable-libspeex --enable-libmp3lame --enable-libopenjpeg --enable-libxvid -
-enable-libschroedinger --enable-libx264
  libavutil     50. 3. 0 / 50. 3. 0
  libavcodec    52.27. 0 / 52.27. 0
  libavformat   52.32. 0 / 52.32. 0
  libavdevice   52. 2. 0 / 52. 2. 0
  libswscale     0. 7. 1 /  0. 7. 1
  built on Apr 28 2009 04:04:42, gcc: 4.2.4
[flv @ 0x187d650]skipping flv packet: type 18, size 164, flags 0
Input #0, flv, from 'd:\temp\recording.flv':
  Duration: 00:00:07.17, start: 0.001000, bitrate: N/A
    Stream #0.0: Video: flv, yuv420p, 320x240, 1k tbr, 1k tbn, 1k tbc
    Stream #0.1: Audio: nellymoser, 44100 Hz, mono, s16
[libx264 @ 0x13518b0]using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE
4.2
[libx264 @ 0x13518b0]profile Baseline, level 4.2
Output #0, ipod, to 'd:\temp\out.m4v':
    Stream #0.0: Video: libx264, yuv420p, 320x240, q=2-31, 200 kb/s, 1k tbn, 1k
tbc
    Stream #0.1: Audio: libfaac, 22050 Hz, mono, s16, 128 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Press [q] to stop encoding
frame=   90 fps=  0 q=-1.0 Lsize=     128kB time=6.87 bitrate= 152.4kbits/s
video:92kB audio:32kB global headers:1kB muxing overhead 2.620892%
[libx264 @ 0x13518b0]slice I:8     Avg QP:29.62  size:  7047
[libx264 @ 0x13518b0]slice P:82    Avg QP:30.83  size:   467
[libx264 @ 0x13518b0]mb I  I16..4: 17.9%  0.0% 82.1%
[libx264 @ 0x13518b0]mb P  I16..4:  0.6%  0.0%  0.0%  P16..4: 23.1%  0.0%  0.0%
 0.0%  0.0%    skip:76.3%
[libx264 @ 0x13518b0]final ratefactor: 57.50
[libx264 @ 0x13518b0]SSIM Mean Y:0.9544735
[libx264 @ 0x13518b0]kb/s:8412.6


  



  My suspicion is that it has something to do with the audio encoding. If so, does anyone know how to force it to reencode the audio to the proper format ?

  



  Any other ideas ?