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• Further SMC Encoding Work

  25 août 2011, par Multimedia Mike — General

  Sometimes, when I don’t feel like doing anything else, I look at that Apple SMC video encoder again.

  8-bit Encoding
  When I last worked on the encoder, I couldn’t get the 8-color mode working correctly, even though the similar 2- and 4-color modes were working fine. I chalked the problem up to the extreme weirdness in the packing method unique to the 8-color mode. Remarkably, I had that logic correct the first time around. The real problem turned out to be with the 8-color cache and it was due to the vagaries of 64-bit math in C. Bit shifting an unsigned 8-bit quantity implicitly results in a signed 32-bit quantity, or so I discovered.

  Anyway, the 8-color encoding works correctly, thus shaving a few more bytes off the encoding size.

  Encoding Scheme Oddities
  The next step is to encode runs of data. This is where I noticed some algorithmic oddities in the scheme that I never really noticed before. There are 1-, 2-, 4-, 8-, and 16-color modes. Each mode allows encoding from 1-256 blocks of that same encoding. For example, the byte sequence :

    0x62 0x45
  

  Specifies that the next 3 4×4 blocks are encoded with single-color mode (of byte 0×62, high nibble is encoding mode and low nibble is count-1 blocks) and the palette color to be used is 0×45. Further, opcode 0×70 is the same except the following byte allows for specifying more than 16 (i.e., up to 256) blocks shall be encoded in the same matter. In light of this repeat functionality being built into the rendering opcodes, I’m puzzled by the existence of the repeat block opcodes. There are opcodes to repeat the prior block up to 256 times, and there are opcodes to repeat the prior pair of blocks up to 256 times.

  So my quandary is : What would the repeat opcodes be used for ? I hacked the FFmpeg / Libav SMC decoder to output a histogram of which opcodes are used. The repeat pair opcodes are never seen. However, the single-repeat opcodes are used a few times.

  Puzzle Solved ?
  I’m glad I wrote this post. Just as I was about to hit “Publish”, I think I figured it out. I haven’t mentioned the skip opcodes yet– there are opcodes that specify that 1-256 4×4 blocks are unchanged from the previous frame. Conceivably, a block could be unchanged from the previous frame and then repeated 1-256 times from there.

  That’s something I hadn’t thought of up to this point for my proposed algorithm and will require a little more work.

  Further reading

  • My first entry regarding my toy SMC encoder

• Making libmp3lame work with ffmpeg on OS X

  26 janvier 2015, par eco_bach

  I tried this solution
  https://jeppenejsum.wordpress.com/2009/10/27/making-libmp3lame-work-with-ffmpeg-on-os-x/#comments

  but its not working for me. I get no audio when I do my sample ffmpeg conversions in the OSX terminal. ie

  ffmpeg -i MASTER.mp4 -c:v libx264 -preset ultrafast -profile:v high -crf 20 -c:a libmp3lame -q:a 4 output_CRF_20_ultrafast.mp4

  Can any FFMPEG experts suggest what I am doing wrong ? How do I get libmp3lame to work with ffmpeg in OSX Yosemite ?

• Can ffmpeg copy parts from an rmvb file without re-encoding ?

  24 juin 2017, par Eng. M.Hamdy

  I want to fast copy parts from an rmvb file without re-encoding. This command works fine with mp4 files but not with rmbv (I dropped start time and duration here) :

  ffmpeg -i input -c copy output

  when I use it with rmvb like this :

  ffmpeg -i 1.rmvb -c copy 1.mp4

  I get this error :

  [mp4 @ 00bb8980] Could not find tag for codec rv40 in stream #0, codec
  not curre ntly supported in container Could not write header for
  output file #0 (incorrect codec parameters ?) : Invali d argument
  Stream mapping : Stream #0:1 -> #0:0 (copy) Stream #0:0 -> #0:1
  (copy)

  I also tried this :

  ffmpeg -i 1.rmvb -c copy 2.rmvb

  and got this error :

  [NULL @ 04748980] Unable to find a suitable output format for ’2.rmvb’
  2.rmvb : Invalid argument

  I tried this command :

  ffmpeg -i 1.rmvb -c:v copy -c:a aac -strict experimental -b:a 128k 1.mp4

  and got this error :

  [mp4 @ 046e0020] Could not find tag for codec rv40 in stream #0, codec
  not curre ntly supported in container Could not write header for
  output file #0 (incorrect codec parameters ?) : Invali d argument Error
  initializing output stream 0:1 — [aac @ 046e1bc0] Qavg : nan
  Conversion failed !

  I read this topic :
  but the solution does not work for me.. After many trials, this is the command that worked (and took too long time) :

  ffmpeg -i 1.rmvb -c:v libx264 -b:a 32k output.mp4

  But I do not want to re-encode the file. Any solution ?

  Edit :
  I tried :

  ffmpeg -i 1.rmvb -c copy 1.mkv

  ffmpeg version N-86447-gfeb13ae Copyright (c) 2000-2017 the FFmpeg
  developers built with gcc 7.1.0 (GCC) configuration : —enable-gpl
  —enable-version3 —enable-cuda —enable-cuvid —e nable-d3d11va —enable-dxva2 —enable-libmfx —enable-nvenc —enable-avisynth — enable-bzlib —enable-fontconfig —enable-frei0r —enable-gnutls
  —enable-iconv
  —enable-libass —enable-libbluray —enable-libbs2b —enable-libcaca —enable-li bfreetype —enable-libgme —enable-libgsm —enable-libilbc —enable-libmodplug -
  -enable-libmp3lame —enable-libopencore-amrnb —enable-libopencore-amrwb —enabl e-libopenh264 —enable-libopenjpeg —enable-libopus —enable-librtmp —enable-li bsnappy —enable-libsoxr —enable-libspeex —enable-libtheora —enable-libtwolam e —enable-libvidstab —enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx —enable-libwavpack —enable-libwebp —enable-libx264 —enable-libx265 —enable
  -libxavs —enable-libxvid —enable-libzimg —enable-lzma —enable-zlib libavutil 55. 63.100 / 55. 63.100 libavcodec 57. 98.100 /
  57. 98.100 libavformat 57. 73.100 / 57. 73.100 libavdevice 57. 7.100 / 57. 7.100 libavfilter 6. 92.100 / 6. 92.100 libswscale 4. 7.101 / 4. 7.101 libswresample 2. 8.100 /
  2. 8.100 libpostproc 54. 6.100 / 54. 6.100 [rm @ 033a7520] Invalid stream index 2 for index at pos 206099254 Input #0, rm, from
  ’1.rmvb’ : Metadata :
  title : ArabSeed.CoM
  author : ArabSeed.CoM
  copyright : ArabSeed.CoM
  comment :
  ASMRuleBook : #($Bandwidth >= 0),Stream0Bandwidth = 64082, Stream1Bandwi dth = 285918 ;
  Audiences : Easy RealMedia Tool’s Audience ;
  audioMode : music
  Creation Date : 4/22/2010 4:31:14
  Description : This File is Created by Easy RealMedia Tools@ !
  Email : rick@redcheek.net
  Generated By : Easy RealMedia Tools V1.8x
  HomeWeb : http://redcheek.net
  Keywords : ArabSeed.CoM
  Modification Date : 4/22/2010 4:31:14
  videoMode : normal Duration : 01:16:35.69, start : 0.000000, bitrate : 358 kb/s
  Stream #0:0 : Audio : cook (cook / 0x6B6F6F63), 44100 Hz, stereo, fltp, 64 kb/ s
  Stream #0:1 : Video : rv40 (RV40 / 0x30345652), yuv420p, 720x408, 280 kb/s, 25 fps, 25 tbr, 1k tbn, 1k tbc Output #0, matroska, to
  ’1.mkv’ : Metadata :
  title : ArabSeed.CoM
  author : ArabSeed.CoM
  copyright : ArabSeed.CoM
  comment :
  ASMRuleBook : #($Bandwidth >= 0),Stream0Bandwidth = 64082, Stream1Bandwi dth = 285918 ;
  Audiences : Easy RealMedia Tool’s Audience ;
  audioMode : music
  Creation Date : 4/22/2010 4:31:14
  Description : This File is Created by Easy RealMedia Tools@ !
  Email : rick@redcheek.net
  Generated By : Easy RealMedia Tools V1.8x
  HomeWeb : http://redcheek.net
  Keywords : ArabSeed.CoM
  Modification Date : 4/22/2010 4:31:14
  videoMode : normal
  encoder : Lavf57.73.100
  Stream #0:0 : Video : rv40 (RV40 / 0x30345652), yuv420p, 720x408, q=2-31, 280 kb/s, 25 fps, 25 tbr, 1k tbn, 1k tbc
  Stream #0:1 : Audio : cook ([255][255][255][255] / 0xFFFFFFFF), 44100 Hz, ster eo, fltp, 64 kb/s Stream mapping : Stream #0:1 -> #0:0
  (copy) Stream #0:0 -> #0:1 (copy) Press [q] to stop, [?] for help
  [matroska @ 05228980] The Matroska muxer does not yet support muxing
  cook av_interleaved_write_frame() : Not yet implemented in FFmpeg,
  patches welcome Error writing trailer of 1.mkv : Not yet implemented in
  FFmpeg, patches welcome frame= 21 fps=0.0 q=-1.0 Lsize= 0kB
  time=00:00:01.48 bitrate= 0.0kbits /s speed= 148x video:2kB
  audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing ove
  rhead : unknown Conversion failed !

  I also tried :

  ffmpeg -i 1.rmvb -c copy 1.avi
  
  
  
  ffmpeg version N-86447-gfeb13ae Copyright (c) 2000-2017 the FFmpeg developers
  
    built with gcc 7.1.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --e
  
  nable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --
  
  enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv
  
  --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-li
  
  bfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug -
  
  -enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enabl
  
  e-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-li
  
  bsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolam
  
  e --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx
  
   --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable
  
  -libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
  
    libavutil      55. 63.100 / 55. 63.100
  
    libavcodec     57. 98.100 / 57. 98.100
  
    libavformat    57. 73.100 / 57. 73.100
  
    libavdevice    57.  7.100 / 57.  7.100
  
    libavfilter     6. 92.100 /  6. 92.100
  
    libswscale      4.  7.101 /  4.  7.101
  
    libswresample   2.  8.100 /  2.  8.100
  
    libpostproc    54.  6.100 / 54.  6.100
  
  [rm @ 00077520] Invalid stream index 2 for index at pos 206099254
  
  Input #0, rm, from '1.rmvb':
  
    Metadata:
  
      title           : ArabSeed.CoM
  
      author          : ArabSeed.CoM
  
      copyright       : ArabSeed.CoM
  
      comment         :
  
      ASMRuleBook     : #($Bandwidth >= 0),Stream0Bandwidth = 64082, Stream1Bandwi
  
  dth = 285918;
  
      Audiences       : Easy RealMedia Tool's Audience;
  
      audioMode       : music
  
      Creation Date   : 4/22/2010 4:31:14
  
      Description     : This File is Created by Easy RealMedia Tools@!
  
      Email           : rick@redcheek.net
  
      Generated By    : Easy RealMedia Tools V1.8x
  
      HomeWeb         : http://redcheek.net
  
      Keywords        : ArabSeed.CoM
  
      Modification Date: 4/22/2010 4:31:14
  
      videoMode       : normal
  
    Duration: 01:16:35.69, start: 0.000000, bitrate: 358 kb/s
  
      Stream #0:0: Audio: cook (cook / 0x6B6F6F63), 44100 Hz, stereo, fltp, 64 kb/
  
  s
  
      Stream #0:1: Video: rv40 (RV40 / 0x30345652), yuv420p, 720x408, 280 kb/s, 25
  
   fps, 25 tbr, 1k tbn, 1k tbc
  
  Could not write header for output file #0 (incorrect codec parameters ?): Operat
  
  ion not permitted
  
  Stream mapping:
  
    Stream #0:1 -> #0:0 (copy)
  
    Stream #0:0 -> #0:1 (copy)
  
      Last message repeated 1 times