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• Fragmented MP4 not playing in ffplay/QuickTime/Safari, but in VLC

  6 août 2020, par Stack64

  I encoded a fMP4-Video (HEVC) in Swift using VideoToolbox and CoreMedia. The resulting fragmented MP4 is only playing in VLC.

  


  The library I am using to write the fMP4 is an HEVC-adapted version of this GitHub-Project : https://github.com/krad/morsel

  


  Process of encoding and writing :

  


  

  1. VideoToolbox : Encoding SampleBuffer from the camera (VTCompressionSession, as described in WWDC 2014 Session 513)

  


  2. Using CoreMedia-Functions (e.g. CMVideoFormatDescriptionGetHEVCParameterSetAtIndex, CMVideoFormatDescriptionGetDimensions) to get the encoded streams metadata. I am writing the content of CMFormatDescriptionGetExtension(description, extensionKey: "SampleDescriptionExtensionAtoms" as CFString)["hvcC"] directly to the hvcC box. This box is obviously written correctly, when I alter one bit of the box of the mp4, QuickTime throws an error.

  


  3. I am appending the sample buffer data to the morsel-library, which manages fragmentation and creates the moof and mdat atoms.

  


  


  The result file is playable in VLC, when I just let the playback "run" without doing anything. When I scroll the time in VLC, VLC crashes and the playback stops.

  


  It is also sort of "playable" in Safari and QuickTime (no error message shown, the playback window opens and the correct length of the file is shown, I can even change to playback time / play/pause, but there is no video shown. The window remains empty. And that is the problem I have. I need to get an fMP4 running in Safari and QuickTime.

  


  The file is not playing at all in ffplay (same problem when converting with ffmpeg). The line where the playback time is shown remains nan M-V:    nan fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0 , there are no error messages. The playback just does not start.
When playing the file with ffplay, this is the output :

  


  ffplay version 4.3 Copyright (c) 2003-2020 the FFmpeg developers
  built with Apple clang version 11.0.3 (clang-1103.0.32.62)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.3_2 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: mp41mp42isomhlsf
    creation_time   : 2020-08-03T20:41:08.000000Z
  Duration: N/A, bitrate: N/A
    Stream #0:0(und): Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv), 1920x1080, SAR 1:1 DAR 16:9, 1000000000.00 tbr, 1000000000.00 tbn, 1000000000.00 tbc (default)
    Metadata:
      creation_time   : 2020-08-03T20:41:08.000000Z
      handler_name    : video
    nan M-V:    nan fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0 


  


  My file has this structure :

  


  ftyp
moov
    mvhd
    trak
        tkhd
        mdia
            mdhd
            hdlr
            minf
                vmhd
                dinf
                    dref
                stbl
                    stsd
                    stts
                    stsc
                    stsz
                    stco
    mvex
        trex
moof-(1)
mdat
moof-(2)
mdat 
...


  


  The result file I want to create should be like the fMP4 served within this HLS playlist : (Example : https://developer.apple.com/streaming/examples/advanced-stream-hevc.html, Playlist : https://devstreaming-cdn.apple.com/videos/streaming/examples/bipbop_adv_example_hevc/master.m3u8)
This file has the following structure :

  


  ftyp
moov
    mvhd
    trak
        tkhd
        mdia
            mdhd
            hdlr
            minf
                vmhd
                dinf
                    dref
                stbl
                    stsd
                    stts
                    stsc
                    stsz
                    stco
    trak (same structure as above)
    mvex
        trex
moof-(1)
mdat
moof-(2)
mdat 
...


  


  This file from Apple plays perfectly in ffmpeg and QuickTime/Safari. Except for the second trak atom, it has the same structure.

  


  The "good" file is : https://devstreaming-cdn.apple.com/videos/streaming/examples/bipbop_adv_example_hevc/v14/main.mp4 (It is intended for use in a HLS Playlist I've downloaded it with curl)

  


  The "bad" file is : https://www.transfernow.net/ddl/fmp4_bad (link should work, tested it just now :) ). The video shows a slowly rotating sheet of paper.

  


  Any suggestions what the problem with my file is ?
Thanks in advance !

  


• mediastreamvalidator. How can I validate local files

  20 juin 2012, par Agzam

  1) Is there any way to check segmented HLS files if they compliant and correct ?

  I guess mediastreamvalidator from Apple's HTTP Live Streaming Tools should do that, but when I run it against local index.m3u8, it says "Did not receive playlist".

  2) Is there any way to do stream validation on Windows ?

  3) Initially my problem was to do segmenting on Windows, after a lot of hours of searching I've found out that latest ffmpeg can do that. I'm not sure though if it creates correct HLS videos, it doesn't create .m3u8 playlists, which is not a big deal I guess, as long those segments are correct and use Access Unit Delimiter NALs and etc.

• Android, fast video processing

  27 avril 2016, par Ilja Kosynkin

  I have troubles in my current project which requires video processing. Basically crop function (video should be squared), trimming (video shouldn’t be longer than 30 seconds) and quality reduction (bitrate should be equal 713K).
  I’ve succesfully embedded FFmpeg into application, all functions are working quite fine except one major detail - processing as per my boss is taking too long time. For video that have around 52 MB for 36 seconds it’s taking 50 seconds to perforn all the operations (I’m trimming video to 30 seconds before any other operation obviously). The problem is that on parallel project on iOS video processing takes like 10-15 seconds for greater files. I assume that it’s related to fact that they’re using Apple QuickTime format which obviusly was developed by Apple so it’s not surprising that it’s working quite fast.
  So well, it was introduction, now my question : is there any way for Android to process any video in any quality (for now we can assume that all videos are in h264) in time of 10-15 seconds (not more then in 30 seconds, as my boss said) ? Some alternative to FFmpeg, that can perform operations faster ? I’nm pretty sure that there is no possibility to perform such work in a such short time, since I already feel like I searched thought while Internet, but I want to make sure that there is really no possibility to do such work. If anyone can provide me links to solution more faster than FFmpeg or confirm that there is no such solution, I will be very gratefull.

  Update
  Thanks to Alex Cohn I’ve resolved this with MediaCodec. After a while, I got 20 seconds processing on 52MB video with cropping to square and lowering bitrate. For any future Googlers out of here I can suggest to take a look at this respository :
  Many stuff about MediaCodec
  and more precisely at this file : Extract, edit and encode again, video and audio