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• 2011 In Open Source Multimedia

  5 janvier 2012, par Multimedia Mike — Open Source Multimedia

  Sometimes I think that the pace of multimedia technology is slowing down. Obviously, I’m not paying close enough attention. I thought I would do a little 2011 year-end review of what happened in the world of open source multimedia, mainly for my own benefit. Let me know in the comments what I missed.

  The Split
  The biggest deal in open source multimedia was the matter of the project split. Where once stood one project (FFmpeg) there now stands two (also Libav). Where do things stand with the projects now ? Still very separate but similar. Both projects obsessively monitor each other’s git commits and prodigiously poach each other’s work, both projects being LGPL and all. Most features that land in one code base end up in the other. Thus, I refer to FFmpeg and Libav collectively as “the projects”.

  Some philosophical reasons for the split included project stagnation and development process friction. Curiously, these problems are fond memories now and the spirit of competition has pushed development forward at a blinding pace.

  People inside the project have strong opinions about the split ; that’s understandable. People outside the project have strong opinions about the split ; that’s somewhat less understandable, but whatever. After 5 years of working for Adobe on the Flash Player (a.k.a. the most hated software in all existence if internet nerds are to be believed on the matter), I’m so over internet nerd drama.

  For my part, I just try to maintain some appearance of neutrality since I manage some shared resources for the open source multimedia community (like the wiki and samples repo) and am trying to keep them from fracturing as well.

  Apple and Open Source
  It was big news that Apple magnanimously open sourced their lossless audio codec. That sets a great example and precedent.

  New Features
  I mined the 'git log' of the projects in order to pick out some features that were added during 2011.

  First off, Apple’s ProRes video codec was reverse engineered and incorporated into the multimedia libraries. And for some weird reason, this is an item that made the rounds in the geek press. I’m not entirely sure why, but it may have something to do with inter-project conflict. Anyway, here is the decoder in action, playing a video of some wild swine, one of the few samples we have :

  
  
  

  Other new video codecs included a reverse engineered Indeo 4 decoder. Gotta catch ‘em all ! That completes our collection of Indeo codecs. But that wasn’t enough– this year, we got a completely revised Indeo 3 decoder (the previous one, while functional, exhibited a lot of code artifacts betraying a direct ASM ->C translation). Oh, and many thanks to Kostya for this gem :

  
  
  

  That’s the new Origin Xan decoder (best known for Wing Commander IV cinematics) in action, something I first started reverse engineering back in 2002. Thanks to Kostya for picking up my slack yet again.

  Continuing with the codec section, there is a decoder for Adobe Flash Screen Video 2 — big congrats on this ! One of my jobs at Adobe was documenting this format to the outside world and I was afraid I could never quite make it clear enough to build a complete re-implementation. But the team came through.

  Let’s see, there are decoders for VBLE video, Ut Video, Windows Media Image (WMVP/WMP2), Bink audio version ‘b’, H.264 4:2:2 intra frames, and MxPEG video. There is a DPX image encoder, a Cirrus Logic AccuPak video encoder, and a v410 codec.

  How about some more game stuff ? The projects saw — at long last — an SMJPEG demuxer. This will finally allow usage and testing of the SMJPEG IMA ADPCM audio decoder I added about a decade ago. Funny story behind that– I was porting all of my decoders from xine which included the SMJPEG ADPCM. I just never quite got around to writing a corresponding demuxer. Thanks to Paul Mahol for taking care of that.

  Here’s a DFA playback system for a 1995 DOS CD-ROM title called Chronomaster. No format is too obscure, nor its encoded contents too cheesy :

  
  
  

  There’s now a demuxer for a format called XMV that was (is ?) prevalent on Xbox titles. Now the projects can handle FMV files from many Xbox games, such as Thrillville.

  
  
  

  The projects also gained the ability to play BMV files. I think this surfing wizard comes from Discworld II. It’s non-computer-generated animation at a strange resolution.

  
  
  

  More demuxers : xWMA, PlayStation Portable PMP format, and CRI ADX format ; muxer for OpenMG audio and LATM muxer/demuxer.

  One more thing : an AVX-optimized fast Fourier transform (FFT). If you have a machine that supports AVX, there’s no way you’ll even notice the speed increase of a few measly FFT calls for audio coding/decoding, but that’s hardly the point. The projects always use everything on offer for any CPU.

  Please make me aware of features that I missed in the list !

  Continuous Testing
  As a result of the split, each project has its own FATE server, one for FFmpeg and one for Libav. As of the new year, FFmpeg has just over 1000 tests while Libav had 965. This is one area where I’m obviously ecstatic to see competition. Some ad-hoc measurements on my part indicate that the total code coverage via the FATEs has not appreciably increased. But that’s a total percentage. Both the test count and the code count have been steadily rising.

  Google Summer of Code and Google Code-In
  Once again, the projects were allowed to participate in the Google Summer of Code as well as Google Code-In. I confess that I didn’t keep up with these too carefully (and Code-In is still in progress as of this writing). I do know that the project split occurred after FFmpeg had already been accepted for GSoC season 2011 and the admins were gracious enough to allow FFmpeg and Libav to allow both projects to participate in the same slot as long as they could both be mature about it.

  Happy New Year
  Let’s see what we can accomplish in 2012.

• run ffmpeg with multiple threads

  12 février 2012, par xhammer

  Ok i have learnt how to convert videos files using vb.net and ffmpeg. But as far as i know we cannot use multiple threads to run same exe file to convert files. Do you know how i can convert multiple videos using one external exe file (ffmpeg) ?

  I have not tried because my computer time was over. So iam just asking a general doubt whether if we attach it to one process then wouldn't the process get locked ? Then can we multi-thread this application or not ?

  Thanks in advance.

• Encode x264 video with ffmpeg for Android with starting offset

  4 août 2013, par scubed

  I'm trying to convert a video to play on an Android device.
  The video is from a big movie. I am chopping it back into pieces
  to correspond with the actual segments of the movie using -ss and -t.

  The input is mp4 with H.264 and AAC.
  The output is mkv using H.264 and Vorbis.

  Specifically, the input is :

  Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 320x240, 2240 kb/s, 29.97 fps, 60 tbr, 90k tbn, 180k tbc
  
  Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, s16, 162 kb/s

  I'm using : ffmpeg version 1.0.7

  The command I'm trying is something like :

  ffmpeg -ss 00:03:52.000 -i in.mp4 -t 00:01:00.000 -c:v libx264 -preset medium -crf 20 -maxrate 400k -bufsize 1835k -c:a libvorbis -sn out.mkv

  However, while the resulting video works fine on my computer, when I click on
  my phone, it says : Can't play video
  and checking the Android log, it has :

  E/SoftAVC (24319): Decoder failed: -2
  
  E/OMXCodec(24319): [OMX.google.h264.decoder] ERROR(0x80001001, -1007)

  It is still able to make a thumbnail for the movie, but not play it.

  Interestingly, some simple variations of that command do work :
  Remove -ss to start at the beginning of the video
  Use -an to disable audio

  These variations still failed :
  Copying the original audio with -c:a copy, or other audio codecs like vorbis, mp3
  Using mp4 instead of mkv
  Using baseline H.264 profile, including restricting level to 1.2.

  Running through mkvmerge first not only fails, but makes Android not able to even make a thumbnail.

  I don't know if it is related, but another small thing I noticed is that for
  starting transcoding later in the movie, the audio starts out slightly out-of-sync.
  After several seconds, it gets back in sync. The audio is in sync in the original.

  Robert Rowntree :

  -vcodec libx264 -b:v 200k -bt 50k -threads 0 -b_strategy 1 -acodec copy -f mp4 -strict -2

  Interesting. Your command almost works. The video actually plays on Android. The one problem is that the audio is out-of-sync and stays out-of-sync throughout the whole clip. But, that's much closer than I've been. I'll search around there and see if I can find the right combination.

  I tried combinations of it. It appears that using both mp4 and copying the audio is what allows it to work. Using libvorbis or going to mkv breaks it again. But, I would like to transcode the audio, and I suspect to keep it in sync, I might have to transcode it anyways. Note that even with transcoding, when I play it back on the computer, I still don't have sync between audio and video.

  LordNeckbeard :
  Here is the complete log.

  ffmpeg version 1.0.7 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Jul 27 2013 13:01:19 with gcc 4.4.5 (Gentoo 4.4.5 p1.2, pie-0.4.5)
  
    configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --enable-shared --cc=x86_64-pc-linux-gnu-gcc --cxx=x86_64-pc-linux-gnu-g++ --ar=x86_64-pc-linux-gnu-ar --optflags='-mtune=athlon64 -O2 -pipe -fomit-frame-pointer -fstack-protector' --extra-cflags='-mtune=athlon64 -O2 -pipe -fomit-frame-pointer -fstack-protector' --extra-cxxflags='-mtune=athlon64 -O2 -pipe -fomit-frame-pointer -fstack-protector' --disable-static --enable-gpl --enable-version3 --enable-postproc --enable-avfilter --enable-avresample --disable-stripping --disable-debug --disable-doc --disable-vaapi --disable-runtime-cpudetect --enable-libmp3lame --enable-libvo-aacenc --enable-libtheora --enable-libx264 --enable-libxvid --enable-libcaca --enable-openal --disable-indev=v4l2 --disable-indev=oss --disable-indev=jack --enable-x11grab --disable-outdev=oss --enable-libfreetype --enable-pthreads --enable-libspeex --enable-libvorbis --disable-altivec --disable-avx --disable-vis --disable-neon --cpu=athlon64 -  libavutil      51. 73.101 / 51. 73.101
  
    libavcodec     54. 59.100 / 54. 59.100
  
    libavformat    54. 29.104 / 54. 29.104
  
    libavdevice    54.  2.101 / 54.  2.101
  
    libavfilter     3. 17.100 /  3. 17.100
  
    libswscale      2.  1.101 /  2.  1.101
  
    libswresample   0. 15.100 /  0. 15.100
  
    libpostproc    52.  0.100 / 52.  0.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'in.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: mp42isomavc1
  
      creation_time   : 2013-07-13 02:23:51
  
      encoder         : HandBrake 0.9.6 2012022800
  
    Duration: 03:14:01.41, start: 0.000000, bitrate: 2408 kb/s
  
      Chapter #0.0: start -0.133467, end 648.697411
  
      Metadata:
  
        title           : Chapter  1
  
      Chapter #0.1: start 648.697411, end 1297.345411
  
      Metadata:
  
        title           : Chapter  2
  
      Chapter #0.2: start 1297.345411, end 1729.777411
  
      Metadata:
  
        title           : Chapter  3
  
      Chapter #0.3: start 1729.777411, end 2378.425411
  
      Metadata:
  
        title           : Chapter  4
  
      Chapter #0.4: start 2378.425411, end 3027.073411
  
      Metadata:
  
        title           : Chapter  5
  
      Chapter #0.5: start 3027.073411, end 3675.721411
  
      Metadata:
  
        title           : Chapter  6
  
      Chapter #0.6: start 3675.721411, end 4108.153411
  
      Metadata:
  
        title           : Chapter  7
  
      Chapter #0.7: start 4108.153411, end 4756.801411
  
      Metadata:
  
        title           : Chapter  8
  
      Chapter #0.8: start 4756.801411, end 5405.449411
  
      Metadata:
  
        title           : Chapter  9
  
      Chapter #0.9: start 5405.449411, end 6054.097411
  
      Metadata:
  
        title           : Chapter 10
  
      Chapter #0.10: start 6054.097411, end 6702.745411
  
      Metadata:
  
        title           : Chapter 11
  
      Chapter #0.11: start 6702.745411, end 7135.177411
  
      Metadata:
  
        title           : Chapter 12
  
      Chapter #0.12: start 7135.177411, end 7783.825411
  
      Metadata:
  
        title           : Chapter 13
  
      Chapter #0.13: start 7783.825411, end 8432.473411
  
      Metadata:
  
        title           : Chapter 14
  
      Chapter #0.14: start 8432.473411, end 9081.121411
  
      Metadata:
  
        title           : Chapter 15
  
      Chapter #0.15: start 9081.121411, end 9513.553411
  
      Metadata:
  
        title           : Chapter 16
  
      Chapter #0.16: start 9513.553411, end 10162.201411
  
      Metadata:
  
        title           : Chapter 17
  
      Chapter #0.17: start 10162.201411, end 10810.849411
  
      Metadata:
  
        title           : Chapter 18
  
      Chapter #0.18: start 10810.849411, end 11459.497411
  
      Metadata:
  
        title           : Chapter 19
  
      Chapter #0.19: start 11459.497411, end 11641.412478
  
      Metadata:
  
        title           : Chapter 20
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 320x240, 2240 kb/s, 29.97 fps, 60 tbr, 90k tbn, 180k tbc
  
      Metadata:
  
        creation_time   : 2013-07-13 02:23:51
  
      Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, s16, 162 kb/s
  
      Metadata:
  
        creation_time   : 2013-07-13 02:23:51
  
      Stream #0:2(und): Subtitle: mov_text (text / 0x74786574)
  
      Metadata:
  
        creation_time   : 2013-07-13 02:23:51
  
  [libx264 @ 0x14ea220] using cpu capabilities: MMX2 SSE2Slow SlowCTZ
  
  [libx264 @ 0x14ea220] profile High, level 2.1
  
  [libx264 @ 0x14ea220] 264 - core 120 - H.264/MPEG-4 AVC codec - Copyleft 2003-2011 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=60 keyint_min=6 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=20.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 vbv_maxrate=400 vbv_bufsize=1835 crf_max=0.0 nal_hrd=none ip_ratio=1.40 aq=1:1.00
  
  Output #0, matroska, to 'out.mkv':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: mp42isomavc1
  
      encoder         : Lavf54.29.104
  
      Chapter #0.0: start 0.000000, end 60.000000
  
      Metadata:
  
        title           : Chapter  1
  
      Stream #0:0(und): Video: h264 (H264 / 0x34363248), yuv420p, 320x240, q=-1--1, 1k tbn, 60 tbc
  
      Metadata:
  
        creation_time   : 2013-07-13 02:23:51
  
      Stream #0:1(und): Audio: vorbis (oV[0][0] / 0x566F), 48000 Hz, stereo, flt
  
      Metadata:
  
        creation_time   : 2013-07-13 02:23:51
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 -> libx264)
  
    Stream #0:1 -> #0:1 (aac -> libvorbis)
  
  Press [q] to stop, [?] for help
  
  frame= 1799 fps= 92 q=-1.0 Lsize=    3738kB time=00:00:59.98 bitrate= 510.5kbits/s dup=0 drop=51    =51    
  
  video:3016kB audio:683kB subtitle:0 global headers:4kB muxing overhead 0.939943%
  
  [libx264 @ 0x14ea220] frame I:31    Avg QP:20.23  size: 14126
  
  [libx264 @ 0x14ea220] frame P:634   Avg QP:23.03  size:  3317
  
  [libx264 @ 0x14ea220] frame B:1134  Avg QP:27.71  size:   482
  
  [libx264 @ 0x14ea220] consecutive B-frames:  2.3% 12.8% 84.7%  0.2%
  
  [libx264 @ 0x14ea220] mb I  I16..4:  3.8% 63.8% 32.4%
  
  [libx264 @ 0x14ea220] mb P  I16..4:  0.1%  0.3%  0.1%  P16..4: 47.4% 30.2% 19.5%  0.0%  0.0%    skip: 2.4%
  
  [libx264 @ 0x14ea220] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8: 35.2%  3.0%  0.6%  direct: 8.8%  skip:52.3%  L0:28.7% L1:63.9% BI: 7.4%
  
  [libx264 @ 0x14ea220] 8x8 transform intra:64.0% inter:59.5%
  
  [libx264 @ 0x14ea220] coded y,uvDC,uvAC intra: 94.2% 99.5% 95.5% inter: 23.3% 55.5% 14.0%
  
  [libx264 @ 0x14ea220] i16 v,h,dc,p: 75% 10%  5% 10%
  
  [libx264 @ 0x14ea220] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 16% 12%  8%  7%  8%  8% 11% 11%
  
  [libx264 @ 0x14ea220] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 17% 20%  7%  8%  9%  9% 10% 10% 11%
  
  [libx264 @ 0x14ea220] i8c dc,h,v,p: 38% 31% 14% 17%
  
  [libx264 @ 0x14ea220] Weighted P-Frames: Y:7.3% UV:4.4%
  
  [libx264 @ 0x14ea220] ref P L0: 48.8% 14.2% 29.1%  7.5%  0.4%
  
  [libx264 @ 0x14ea220] ref B L0: 65.4% 30.8%  3.7%
  
  [libx264 @ 0x14ea220] ref B L1: 89.0% 11.0%
  
  [libx264 @ 0x14ea220] kb/s:411.70