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• avformat/matroskadec : Improve forward compability

  25 mars 2020, par Andreas Rheinhardt

  avformat/matroskadec : Improve forward compability
  Matroska is built around the principle that a reader does not need to
  
  understand everything in a file in order to be able to make use of it ;
  
  it just needs to ignore the data it doesn't know about.
  Our demuxer typically follows this principle, but there is one important
  
  instance where it does not : A Block belonging to a TrackEntry with no
  
  associated stream is treated as invalid data (i.e. the demuxer will try
  
  to resync to the next level 1 element because it takes this as a sign
  
  that it has lost sync). Given that we do not create streams if we don't
  
  know or don't support the type of the TrackEntry, this impairs this
  
  demuxer's forward compability.
  Furthermore, ignoring Blocks belonging to a TrackEntry without
  
  corresponding stream can (in future commits) also be used to ignore
  
  TrackEntries with obviously bogus entries without affecting the other
  
  TrackEntries (by not creating a stream for said TrackEntry).
  Finally, given that matroska_find_track_by_num() already emits its own
  
  error message in case there is no TrackEntry with a given TrackNumber,
  
  the error message (with level AV_LOG_INFO) for this can be removed.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/matroskadec.c

• Revision 229 : Fixed line endings and file properties.

  16 juin 2011, par marc.noirot

  Changed Paths :
   Modify /trunk/AUTHORS

  
   Modify /trunk/CMakeLists.txt

  
   Modify /trunk/COPYING

  
   Modify /trunk/ChangeLog

  
   Modify /trunk/INSTALL

  
   Modify /trunk/Makefile.am

  
   Modify /trunk/NEWS

  
   Modify /trunk/README

  
   Modify /trunk/THANKS

  
   Modify /trunk/TODO

  
   Modify /trunk/config-cmake.h.in

  
   Modify /trunk/configure.ac

  
   Modify /trunk/schemas/Amf0.xsd

  
   Modify /trunk/schemas/Makefile.am

  
   Modify /trunk/schemas/TestAmf0.xml

  
   Modify /trunk/schemas/TestFlv.xml

  
   Modify /trunk/schemas/TestReport.xml

  
   Modify /trunk/schemas/flv.xsd

  
   Modify /trunk/schemas/report.xsd

  
   Modify /trunk/src/CMakeLists.txt

  
   Modify /trunk/src/check.c

  
   Modify /trunk/src/check.h

  
   Modify /trunk/src/compat/getopt.c

  
   Modify /trunk/src/compat/getopt.h

  
   Modify /trunk/src/compat/getopt1.c

  
   Modify /trunk/src/compat/gettext.h

  
   Modify /trunk/src/compat/win32_tmpfile.c

  
   Modify /trunk/src/compat/win32_tmpfile.h

  
   Modify /trunk/src/dump_raw.c

  
   Modify /trunk/src/dump_raw.h

  
   Modify /trunk/src/libyaml/CMakeLists.txt

  
   Modify /trunk/src/libyaml/Makefile.am

  
   Modify /trunk/src/libyaml/api.c

  
   Modify /trunk/src/libyaml/config.h

  
   Modify /trunk/src/libyaml/dumper.c

  
   Modify /trunk/src/libyaml/emitter.c

  
   Modify /trunk/src/libyaml/loader.c

  
   Modify /trunk/src/libyaml/parser.c

  
   Modify /trunk/src/libyaml/reader.c

  
   Modify /trunk/src/libyaml/scanner.c

  
   Modify /trunk/src/libyaml/writer.c

  
   Modify /trunk/src/libyaml/yaml.h

  
   Modify /trunk/src/libyaml/yaml_private.h

  
   Modify /trunk/src/update.c

  
   Modify /trunk/src/update.h

  
   Modify /trunk/src/util.c

  
   Modify /trunk/src/util.h

  
   Modify /trunk/tests/Makefile.am

  
   Modify /trunk/tests/check_amf.c

  
   Modify /trunk/tests/check_flv.c

  
  
  Fixed line endings and file properties.

• FFMPEG throws error while converting WEBM/MP4 audio files from MediaRecorder to MP3

  27 septembre 2022, par Sahil Malik

  I use MediaRecorder to record the audio from the browser and then upload it to my server (ARM-based Linux machine - AWS Lambda Function, if it matters). Based on the browser type, I get either an MP4 file (for the Safari browser) OR a WEBM file (for every other browser) from the MediaRecorder. The audio is converted to Base64 string and posted to my server with FFMPEG.

  


  MediaRecorder implementation

  


  const audioStream = await navigator.mediaDevices.getUserMedia(mediaConstraints);
const MediaRecorder = window['MediaRecorder'];
const mimeType = MediaRecorder.isTypeSupported('audio/webm') ? 'audio/webm' : 'audio/mp4';
const recordingFileExtension = MediaRecorder.isTypeSupported('audio/webm') ? 'webm' : 'mp4';
mediaRecorder = new MediaRecorder(audioStream, { mimeType });
mediaRecorder.ondataavailable = convertBlobAndUploadChunk;
mediaRecorder.start(30 * 1000); // timeslice needs to be in ms
// When user stops recording
mediaRecorder.stop();
audioStream.getTracks().forEach( t => { t.stop(); });
// To convert the audio blob to string
function convertBlobToBase64(blob) {
    return new Promise((resolve, reject) => {
        const reader = new FileReader();
        reader.readAsDataURL(blob);
        reader.onload = () => {
            const tmpStr = reader.result.toString();
            resolve(tmpStr.substring(tmpStr.indexOf('base64,') + 7));
        };
        reader.onerror = error => reject(error);
    });
}

let blobCount = 0;
async function convertBlobAndUploadChunk(blobEvent) {
    if (!blobEvent.data || blobEvent.data.size === 0) return;

    blobCount++;

    const recordData = JSON.stringify({
        M: {
            blobCount,
            //some other meta data
        },
        D: await convertBlobToBase64(audioBlob),
    });

    await angularHttpClient.post(apiUrl, recordData, new HttpHeaders({
        'Content-Type': 'application/json',
        'x-api-key': apiKey,
    })).toPromise();
}


  


  On my server, I convert the WEBM/MP4 file to an MP3 file for better cross-browser compatibility and to enable scrubbing.

  


  Backend Lambda Implementation

  


  const FFMpegCommand = require('fluent-ffmpeg'); // v2.1.2
new FFMpegCommand()
        .input(originalFile)
        .on('end', (error, stdOut, stdError) => {
            if (error) {
                console.error(error);
            }
        })
        .save(convertedFile);


  


  This works perfectly fine 99.9% of the time but FFMPEG throws one of the following errors for 0.1% of the time :

  


  Error 1 : Invalid data found when processing input

  


  error reading header

  


  ffmpeg version 4.4-static https://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2021 the 
FFmpeg developers
built with gcc 8 (Debian 8.3.0-6)
configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7232f40] could not find corresponding trex (id 1)
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7232f40] could not find corresponding track id 0
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7232f40] trun track id unknown, no tfhd was found
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7232f40] error reading header
/tmp/long-filename-of-140chars-to-keep-files-unique.mp4: Invalid data found when processing input


  


  EBML Header parsing failed

  


  ffmpeg version 4.4-static https://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 8 (Debian 8.3.0-6)
configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
[matroska,webm @ 0x7595f40] Format matroska,webm detected only with low score of 1, misdetection possible!
[matroska,webm @ 0x7595f40] EBML header parsing failed
/tmp/long-filename-of-140chars-to-keep-files-unique.webm: Invalid data found when processing input


  


  No specific details

  


  ffmpeg version 4.4-static https://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 8 (Debian 8.3.0-6)
configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
/tmp/long-filename-of-140chars-to-keep-files-unique.webm: Invalid data found when processing input


  


  Error 2 : Output file #0 does not contain any stream

  


  ffmpeg version 4.4-static https://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 8 (Debian 8.3.0-6)
configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
[mpegts @ 0x5d19f40] Format mpegts detected only with low score of 2, misdetection possible!
[mpegts @ 0x5d19f40] Could not detect TS packet size, defaulting to non-FEC/DVHS
Input #0, mpegts, from '/tmp/long-filename-of-140chars-to-keep-files-unique.webm':
Duration: N/A, bitrate: N/A
Output #0, mp3, to '/tmp/long-filename-of-140chars-to-keep-files-unique.mp3':
Output file #0 does not contain any stream


  


  Thanks for reading, any help/suggestion is highly appreciated.