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• On ALAC’s Open Sourcing

  1er novembre 2011, par Multimedia Mike — Codec Technology

  Apple open sourced their lossless audio codec last week. Pretty awesome ! I have a theory that, given enough time, absolutely every codec will be open source in one way or another.

  I know I shouldn’t bother reading internet conversation around any news related to multimedia technology. And if I do read it, I shouldn’t waste any effort getting annoyed about them. But here are some general corrections :

  • ALAC is not in the same league as — nor is it a suitable replacement for — MP3/AAC/Vorbis or any other commonly used perceptual audio codec. It’s not a matter of better or worse ; they’re just different families of codecs designed for different purposes.
  • Apple open sourced ALAC, not AAC– easy mistake, though there’s nothing to ‘open source’ about AAC (though people can, and will, argue about its absolute ‘open-ness’).
  • There’s not much technical room to argue between ALAC and FLAC, the leading open source lossless audio compressor. Both perform similarly in terms of codec speeds (screamingly fast) and compression efficiency (results vary slightly depending on source material).
  • Perhaps the most frustrating facet is the blithe ignorance about ALAC’s current open source status. While this event simply added an official “open source” status to the codec, ALAC has effectively been open source for a very long time. According to my notes, the ALAC decoding algorithm was reverse engineered in 2005 and added into FFmpeg in March of the same year. Then in 2008, Google — through their Summer of Code program — sponsored an open source ALAC encoder.

  From the multimedia-savvy who are versed in these concepts, the conversation revolves around which would win in a fight, ALAC or FLAC ? And who between Apple and FFmpeg/Libav has a faster ALAC decoder ? The faster and more efficient ALAC encoder ? I contend that these issues don’t really matter. If you have any experience working with lossless audio encoders, you know that they tend to be ridiculously fast to both encode and decode and that many different lossless codecs compress at roughly the same ratios.

  As for which encoder is the fastest : use whatever encoder is handiest and most familiar, either iTunes or FFmpeg/Libav.

  As for whether to use FLAC or ALAC — if you’ve already been using one or the other for years, keep on using it. Support isn’t going to vanish. If you’re deciding which to use for a new project, again, perhaps choose based on software you’re already familiar with. Also, consider hardware support– ALAC enjoys iPod support, FLAC is probably better supported in a variety of non-iPod devices, though that may change going forward due to this open sourcing event.

  For my part, I’m just ecstatic that the question of moral superiority based on open source status has been removed from the equation.

  Code-wise, I’m interested in studying the official ALAC code to see if it has any corner-case modes that the existing open source decoders don’t yet account for. The source makes mention of multichannel (i.e., greater than stereo) configurations, but I don’t know if that’s in FFmpeg/Libav.

• Encode loopback capture data in mp3 using ffmpeg in VC++

  16 octobre 2013, par NetCoder89

  I'm trying to work on loopback capture(What you hear) and record this file in mp3/aac format using VC++.
   >I can capture audio and can create a .wav file i.e. not compressed but I want a compressed file so I'm encoding this through ffmpeg to write an mp3 file not a .wav.

  However I'm not getting any way to do it directly ?
  I referred this for loopback capture.

  Please share your experience and opinions.

  Thanks !

• ffmpeg : Generate video from picture

  16 octobre 2013, par Tchoupi

  I'm currently trying to generate a video from a single picture (1980*1024)
  Here my cmd :

  ffmpeg -threads 8 -r 1 -loop 1 -i "C:\Library\Titling\__Resources\1.jpg" -t 5.00 -pix_fmt yuv420p -vcodec libx264 -b:v 1500k -s 720:576 -aspect 1.0000 -y "D:\Records\2013-10-11_115453\PublishingDirectory\Temporary_WithtoutAudio1.mp4"

  here cmd execution :

  ffmpeg version N-56297-g7ac6c63 Copyright (c) 2000-2013 the FFmpeg developers
  
  built on Sep 15 2013 18:02:28 with gcc 4.7.3 (GCC)
  
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libblu
  
  ray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
  
  ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-li
  
  bvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  
  libavutil 52. 43.100 / 52. 43.100
  
  libavcodec 55. 31.101 / 55. 31.101
  
  libavformat 55. 16.102 / 55. 16.102
  
  libavdevice 55. 3.100 / 55. 3.100
  
  libavfilter 3. 84.100 / 3. 84.100
  
  libswscale 2. 5.100 / 2. 5.100
  
  libswresample 0. 17.103 / 0. 17.103
  
  libpostproc 52. 3.100 / 52. 3.100
  
  Input #0, image2, from 'C:\Library\Titling\__Resources\1.jpg':
  
  Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
  
  Stream #0:0: Video: mjpeg, yuvj420p(pc), 1920x1080 [SAR 96:96 DAR 16:9], 25 fps, 25 tbr, 25 tbn, 25 tbc
  
  [swscaler @ 025bec00] deprecated pixel format used, make sure you did set range correctly
  
  [libx264 @ 025b7ce0] using SAR=4/5
  
  [libx264 @ 025b7ce0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  
  [libx264 @ 025b7ce0] profile High, level 2.2
  
  [libx264 @ 025b7ce0] 264 - core 135 r2345 f0c1c53 - H.264/MPEG-4 AVC codec - Copyleft 2003-2013 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subm
  
  e=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=12 lookahead_threads=2 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=250 keyint_min=1 scenecut=40 intra_refresh=0 rc_lookahead=40 rc
  
  =abr mbtree=1 bitrate=1500 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'D:\Records\2013-10-11_115453\PublishingDirectory\Temporary_WithtoutAudio1.mp4':
  
  Metadata:
  
  encoder : Lavf55.16.102
  
  Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 720x576 [SAR 4:5 DAR 1:1], q=-1--1, 1500 kb/s, 16384 tbn, 1 tbc
  
  Stream mapping:
  
  Stream #0:0 -> #0:0 (mjpeg -> libx264)
  
  Press [q] to stop, [?] for help
  
  frame= 5 fps=0.0 q=-1.0 Lsize= 64kB time=00:00:03.00 bitrate= 174.0kbits/s
  
  video:63kB audio:0kB subtitle:0 global headers:0kB muxing overhead 1.355758%
  
  [libx264 @ 025b7ce0] frame I:1 Avg QP: 0.00 size: 63203
  
  [libx264 @ 025b7ce0] frame P:1 Avg QP: 0.00 size: 250
  
  [libx264 @ 025b7ce0] frame B:3 Avg QP: 0.00 size: 64
  
  [libx264 @ 025b7ce0] consecutive B-frames: 20.0% 0.0% 0.0% 80.0%
  
  [libx264 @ 025b7ce0] mb I I16..4: 78.8% 4.0% 17.2%
  
  [libx264 @ 025b7ce0] mb P I16..4: 0.0% 0.0% 0.0% P16..4: 1.2% 0.0% 0.1% 0.0% 0.0% skip:98.6%
  
  [libx264 @ 025b7ce0] mb B I16..4: 0.0% 0.0% 0.0% B16..8: 0.9% 0.0% 0.0% direct: 0.0% skip:99.0% L0:12.8% L1:87.2% BI: 0.0%
  
  [libx264 @ 025b7ce0] final ratefactor: -14.43
  
  [libx264 @ 025b7ce0] 8x8 transform intra:4.0% inter:0.0%
  
  [libx264 @ 025b7ce0] coded y,uvDC,uvAC intra: 22.8% 24.1% 24.1% inter: 0.2% 0.0% 0.0%
  
  [libx264 @ 025b7ce0] i16 v,h,dc,p: 93% 1% 4% 2%
  
  [libx264 @ 025b7ce0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 26% 19% 13% 6% 6% 7% 7% 12% 4%
  
  [libx264 @ 025b7ce0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 23% 15% 11% 7% 7% 9% 7% 14% 6%
  
  [libx264 @ 025b7ce0] i8c dc,h,v,p: 85% 4% 6% 5%
  
  [libx264 @ 025b7ce0] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 025b7ce0] kb/s:101.83

  At this step I have two problems :
  first is a warning during execution
  deprecated pixel format used, make sure you did set range correctly
  The second is the video do not work correctly in VLC (video is "black") but it work in wmp...
  

  Then I add an empty audio track :

  ffmpeg -threads 8 -f lavfi -i aevalsrc=0 -i "D:\Records\2013-10-11_115453\PublishingDirectory\Temporary_WithtoutAudio1.mp4" -vcodec copy -b:v 1500k -acodec aac -map 1:0 -map 0:0 -shortest -strict experimental -y "D:\Records\2013-10-11_115453\PublishingDirectory\Temporary1.mp4"

  After that I concat this video to others using complex filter .
  When I concat my videos I have this message :
  

  [output stream 0:1 @ 0451d3a0] 100 buffers queued in output stream 0:1, something may be wrong.

  And when i Watch the result my video freeze after the image insertion for a approximatly a seconde .
  perhaps it is not related
  I don't know ...

  Here my concat command and execution log
  

  D:\test>ffmpeg.exe -threads 8 -i "D:\Records\2013-10-11_115453\PublishingDirectory\Temporary0.mp4" -i "D:\Records\2013-10-11_115453\PublishingDirectory\Temporary1.mp4" -i "D:\Records\2013-10-11_115
  
  453\PublishingDirectory\Temporary2.mp4" -filter_complex "[0:v] [0:a] [1:v] [1:a] [2:v] [2:a] concat=n=3:v=1:a=1 [v] [a] " -map "[v]" -map "[a]" -vcodec libx264 -b 1500000 -s 720:576 -y "D:\Records\
  
  2013-10-11_115453\PublishingDirectory\EditedVideo.mp4"

  ..

  ffmpeg version N-56297-g7ac6c63 Copyright (c) 2000-2013 the FFmpeg developers
  
  built on Sep 15 2013 18:02:28 with gcc 4.7.3 (GCC)
  
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libblu
  
  ray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
  
  ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-li
  
  bvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  
  libavutil 52. 43.100 / 52. 43.100
  
  libavcodec 55. 31.101 / 55. 31.101
  
  libavformat 55. 16.102 / 55. 16.102
  
  libavdevice 55. 3.100 / 55. 3.100
  
  libavfilter 3. 84.100 / 3. 84.100
  
  libswscale 2. 5.100 / 2. 5.100
  
  libswresample 0. 17.103 / 0. 17.103
  
  libpostproc 52. 3.100 / 52. 3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\Records\2013-10-11_115453\PublishingDirectory\Temporary0.mp4':
  
  Metadata:
  
  major_brand : isom
  
  minor_version : 512
  
  compatible_brands: isomiso2avc1mp41
  
  title : Wildlife in HD
  
  encoder : Lavf54.22.100
  
  comment : Footage: Small World Productions, Inc; Tourism New Zealand | Producer: Gary F. Spradling | Music: Steve Ball
  
  copyright : ┬® 2008 Microsoft Corporation
  
  Duration: 00:00:13.70, start: 0.000000, bitrate: 1914 kb/s
  
  Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 720x576 [SAR 4:5 DAR 1:1], 1778 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
  
  Metadata:
  
  handler_name : VideoHandler
  
  Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
  
  Metadata:
  
  handler_name : SoundHandler
  
  Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\Records\2013-10-11_115453\PublishingDirectory\Temporary1.mp4':
  
  Metadata:
  
  major_brand : isom
  
  minor_version : 512
  
  compatible_brands: isomiso2avc1mp41
  
  encoder : Lavf55.16.102
  
  Duration: 00:00:05.00, start: 0.023220, bitrate: 106 kb/s
  
  Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 720x576 [SAR 4:5 DAR 1:1], 102 kb/s, 1 fps, 1 tbr, 16384 tbn, 2 tbc (default)
  
  Metadata:
  
  handler_name : VideoHandler
  
  Stream #1:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 1 kb/s (default)
  
  Metadata:
  
  handler_name : SoundHandler
  
  Input #2, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\Records\2013-10-11_115453\PublishingDirectory\Temporary2.mp4':
  
  Metadata:
  
  major_brand : isom
  
  minor_version : 512
  
  compatible_brands: isomiso2avc1mp41
  
  title : Wildlife in HD
  
  encoder : Lavf54.22.100
  
  comment : Footage: Small World Productions, Inc; Tourism New Zealand | Producer: Gary F. Spradling | Music: Steve Ball
  
  copyright : ┬® 2008 Microsoft Corporation
  
  Duration: 00:00:16.47, start: 0.000000, bitrate: 2761 kb/s
  
  Stream #2:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 720x576 [SAR 4:5 DAR 1:1], 2625 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
  
  Metadata:
  
  handler_name : VideoHandler
  
  Stream #2:1(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
  
  Metadata:
  
  handler_name : SoundHandler
  
  Please use -b:a or -b:v, -b is ambiguous
  
  [libx264 @ 04c748e0] using SAR=4/5
  
  [libx264 @ 04c748e0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  
  [libx264 @ 04c748e0] profile High, level 3.1
  
  [libx264 @ 04c748e0] 264 - core 135 r2345 f0c1c53 - H.264/MPEG-4 AVC codec - Copyleft 2003-2013 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subm
  
  e=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=12 lookahead_threads=2 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=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 r
  
  c=abr mbtree=1 bitrate=1500 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'D:\Records\2013-10-11_115453\PublishingDirectory\EditedVideo.mp4':
  
  Metadata:
  
  major_brand : isom
  
  minor_version : 512
  
  compatible_brands: isomiso2avc1mp41
  
  title : Wildlife in HD
  
  copyright : ┬® 2008 Microsoft Corporation
  
  comment : Footage: Small World Productions, Inc; Tourism New Zealand | Producer: Gary F. Spradling | Music: Steve Ball
  
  encoder : Lavf55.16.102
  
  Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 720x576 [SAR 4:5 DAR 1:1], q=-1--1, 1500 kb/s, 30k tbn, 29.97 tbc
  
  Stream #0:1: Audio: aac (libvo_aacenc) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, s16, 128 kb/s
  
  Stream mapping:
  
  Stream #0:0 (h264) -> concat:in0:v0
  
  Stream #0:1 (aac) -> concat:in0:a0
  
  Stream #1:0 (h264) -> concat:in1:v0
  
  Stream #1:1 (aac) -> concat:in1:a0
  
  Stream #2:0 (h264) -> concat:in2:v0
  
  Stream #2:1 (aac) -> concat:in2:a0
  
  concat:out:v0 -> Stream #0:0 (libx264)
  
  concat:out:a0 -> Stream #0:1 (libvo_aacenc)
  
  Press [q] to stop, [?] for help
  
  [output stream 0:1 @ 0451d3a0] 100 buffers queued in output stream 0:1, something may be wrong.
  
  frame= 1054 fps=101 q=-1.0 Lsize= 7676kB time=00:00:35.23 bitrate=1784.7kbits/s dup=146 drop=0
  
  video:7083kB audio:552kB subtitle:0 global headers:0kB muxing overhead 0.543084%
  
  [libx264 @ 04c748e0] frame I:10 Avg QP:18.41 size: 52713
  
  [libx264 @ 04c748e0] frame P:456 Avg QP:24.04 size: 11772
  
  [libx264 @ 04c748e0] frame B:588 Avg QP:26.20 size: 2308
  
  [libx264 @ 04c748e0] consecutive B-frames: 2.8% 67.9% 1.1% 28.1%
  
  [libx264 @ 04c748e0] mb I I16..4: 23.1% 52.7% 24.2%
  
  [libx264 @ 04c748e0] mb P I16..4: 0.6% 4.3% 1.0% P16..4: 35.8% 18.5% 11.9% 0.0% 0.0% skip:27.8%
  
  [libx264 @ 04c748e0] mb B I16..4: 0.1% 0.8% 0.2% B16..8: 34.2% 5.0% 1.3% direct: 1.3% skip:57.0% L0:37.3% L1:53.3% BI: 9.3%
  
  [libx264 @ 04c748e0] final ratefactor: 23.46
  
  [libx264 @ 04c748e0] 8x8 transform intra:67.7% inter:60.0%
  
  [libx264 @ 04c748e0] coded y,uvDC,uvAC intra: 67.1% 69.5% 30.5% inter: 17.0% 11.0% 0.4%
  
  [libx264 @ 04c748e0] i16 v,h,dc,p: 50% 20% 6% 24%
  
  [libx264 @ 04c748e0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 18% 16% 18% 6% 8% 10% 7% 9% 8%
  
  [libx264 @ 04c748e0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 16% 14% 7% 10% 12% 8% 8% 7%
  
  [libx264 @ 04c748e0] i8c dc,h,v,p: 53% 20% 19% 8%
  
  [libx264 @ 04c748e0] Weighted P-Frames: Y:0.4% UV:0.0%
  
  [libx264 @ 04c748e0] ref P L0: 63.9% 19.2% 11.1% 5.7% 0.0%
  
  [libx264 @ 04c748e0] ref B L0: 90.4% 9.0% 0.6%
  
  [libx264 @ 04c748e0] ref B L1: 97.8% 2.2%
  
  [libx264 @ 04c748e0] kb/s:1649.69

  So How can I Fix my "picture" video ?
  Will it fix the freeze problem after concatenation of videos ?
  If not How can I fix it ?
  

  Thanks in advance !