[FFmpeg-user] Can not resample 6 channels @ 48000 Hz to 6 channels @ 48000

Bernd Butscheidt bbutscheidt at yahoo.de
Sat Mar 26 15:01:57 CET 2011


Hello,

using the given ffmpeg of my gentoo-pc, this works fine:

===============================================
/usr/bin/ffmpeg -ac 6 -r 50 -deinterlace -i Tatort_test.ts -vcodec libx264 -vpre 
fast -maxrate 40000k -bufsize 30000k -crf 12 -wpredp 1 -bf 3 -b_strategy 1 
-vlevel 41 -g 24 -flags2 -bpyramid -slices 4 -subq 1 -refs 1 -flags2 +aud 
-flags2 +dct8x8 -trellis 2 -me_method hex -coder 1 -threads 0 -acodec ac3 -ab 
448k -ac 6 -r 25 -f matroska Tatort_test€reenc.mkv

FFmpeg version SVN-r25767, Copyright (c) 2000-2010 the FFmpeg developers
  built on Mar  5 2011 21:55:02 with gcc 4.5.2
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 
--mandir=/usr/share/man --enable-static --enable-shared 
--cc=x86_64-pc-linux-gnu-gcc --enable-gpl --enable-version3 --enable-postproc 
--enable-avfilter --disable-stripping --disable-debug --disable-doc 
--disable-vaapi --disable-static --enable-libmp3lame --enable-libtheora 
--enable-libvorbis --enable-libx264 --enable-libxvid --enable-libfaac 
--enable-nonfree --disable-indev=oss --disable-indev=jack --enable-x11grab 
--disable-outdev=oss --enable-pthreads --disable-altivec --cpu=athlon64 
--enable-hardcoded-tables
  libavutil     50.33. 0 / 50.33. 0
  libavcore      0.13. 0 /  0.13. 0
  libavcodec    52.96. 0 / 52.96. 0
  libavformat   52.84. 0 / 52.84. 0
  libavdevice   52. 2. 2 / 52. 2. 2
  libavfilter    1.62. 0 /  1.62. 0
  libswscale     0.12. 0 /  0.12. 0
  libpostproc   51. 2. 0 / 51. 2. 0

[h264 @ 0xe14380] mmco: unref short failure
Input #0, mpegts, from 
'Tatort_test.ts':                                                                                                 
 
  Duration: 00:00:59.99, start: 1.400000, bitrate: 12679 kb/s
  Program 1 Service01
    Metadata:
      name            : Service01
      provider_name   : FFmpeg
    Stream #0.0[0x100]: Video: h264, yuv420p, 1280x720 [PAR 1:1 DAR 16:9], 50 
fps, 50 tbr, 90k tbn, 100 tbc
    Stream #0.1[0x101](deu): Audio: ac3, 48000 Hz, stereo, s16, 448 kb/s

...

    Stream #0.0: Video: libx264, yuv420p, 1280x720 [PAR 1:1 DAR 16:9], q=10-51, 
200 kb/s, 1k tbn, 25 tbc
    Stream #0.1(deu): Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Press [q] to stop encoding
==================================================


Doing the same thing with a self-compiled ffmpeg from today I get the mentioned 
error (same file - same call !?!):

=======================================================
/usr/local/bin/ffmpeg -ac 6 -r 50 -deinterlace -i Tatort_test.ts -vcodec libx264 
-vpre fast -maxrate 40000k -bufsize 30000k -crf 12 -wpredp 1 -bf 3 -b_strategy 1 
-vlevel 41 -g 24 -flags2 -bpyramid -slices 4 -subq 1 -refs 1 -flags2 +aud 
-flags2 +dct8x8 -trellis 2 -me_method hex -coder 1 -threads 0 -acodec ac3 -ab 
448k -ac 6 -r 25 -f matroska Tatort_test€reenc.mkv

FFmpeg version UNKNOWN, Copyright (c) 2000-2011 the FFmpeg developers
  built on Mar 26 2011 14:43:55 with gcc 4.5.2
  configuration: --enable-gpl --enable-libx264 --enable-filter=hqdn3d 
--enable-nonfree --enable-libmp3lame --enable-libfaac --enable-frei0r 
--enable-avfilter --enable-version3
  libavutil    50. 40. 0 / 50. 40. 0
  libavcodec   52.115. 0 / 52.115. 0
  libavformat  52.103. 0 / 52.103. 0
  libavdevice  52.  3. 0 / 52.  3. 0
  libavfilter   1. 76. 0 /  1. 76. 0
  libswscale    0. 13. 0 /  0. 13. 0

...

    Stream #0.0[0x100]: Video: h264 (High), yuv420p, 1280x720 [PAR 1:1 DAR 
16:9], 50 fps, 50 tbr, 90k tbn, 100 tbc
    Stream #0.1[0x101](deu): Audio: ac3, 48000 Hz, stereo, s16, 448 kb/s

...

[ac3 @ 0x18883d0] No channel layout specified. The encoder will guess the 
layout, but it might be incorrect.
Output #0, matroska, to 
'Tatort_test€reenc.mkv':                                                                                         
 
  Metadata:
    encoder         : Lavf52.103.0
    Stream #0.0: Video: libx264, yuv420p, 1280x720 [PAR 1:1 DAR 16:9], q=0-69, 
200 kb/s, 1k tbn, 25 tbc
    Stream #0.1(deu): Audio: ac3, 48000 Hz, 5.1, flt, 448 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Press ctrl-c to stop encoding
Input stream #0.1 frame changed from rate:48000 fmt:s16 ch:2 to rate:48000 
fmt:s16 ch:6
Resampling with input channels greater than 2 unsupported.
Can not resample 6 channels @ 48000 Hz to 6 channels @ 48000 
Hz                                                                           

===========================================


In both cases the input audio is not recognized as 6 channel, although mediainfo 
claims to be it this way. Am I missing a compile option because the self 
compiled ffmpeg cannot reencode the input using 6 channels ac3?
Why does ffmpeg not recognize the amount of audio channels:


=====================
mediainfo Tatort_test.ts
General
ID                               : 1 (0x1)
Complete name                    : Tatort_test.ts
Format                           : MPEG-TS
File size                        : 90.7 MiB
Duration                         : 58s 720ms
Overall bit rate                 : 12.9 Mbps

Video
ID                               : 256 (0x100)
Menu ID                          : 1 (0x1)
Format                           : AVC
Format/Info                      : Advanced Video Codec
Format profile                   : High at L4.0
Format settings, CABAC           : Yes
Format settings, ReFrames        : 5 frames
Format settings, GOP             : M=16, N=32
Codec ID                         : 27
Duration                         : 58s 740ms
Bit rate mode                    : Variable
Bit rate                         : 11.8 Mbps
Maximum bit rate                 : 11.5 Mbps
Width                            : 1 280 pixels
Height                           : 720 pixels
Display aspect ratio             : 16:9
Frame rate                       : 50.000 fps
Color space                      : YUV
Chroma subsampling               : 4:2:0
Bit depth                        : 8 bits
Scan type                        : Progressive
Bits/(Pixel*Frame)               : 0.257
Stream size                      : 83.0 MiB (91%)
Color primaries                  : BT.709-5, BT.1361, IEC 61966-2-4, SMPTE RP177
Transfer characteristics         : BT.709-5, BT.1361
Matrix coefficients              : BT.709-5, BT.1361, IEC 61966-2-4 709, SMPTE 
RP177

Audio
ID                               : 257 (0x101)
Menu ID                          : 1 (0x1)
Format                           : AC-3
Format/Info                      : Audio Coding 3
Mode extension                   : CM (complete main)
Codec ID                         : 129
Duration                         : 59s 968ms
Bit rate mode                    : Constant
Bit rate                         : 448 Kbps
Channel(s)                       : 6 channels
Channel positions                : Front: L C R, Side: L R, LFE
Sampling rate                    : 48.0 KHz
Bit depth                        : 16 bits
Compression mode                 : Lossy
Delay relative to video          : -1s 593ms
Stream size                      : 3.20 MiB (4%)
Language                         : German

Menu
ID                               : 4095 (0xFFF)
Menu ID                          : 1 (0x1)
Duration                         : 58s 720ms
List                             : 256 (0x100) (AVC) / 257 (0x101) (AC-3, 
German)
Language                         :  / German
Service name                     : Service01
Service provider                 : FFmpeg
Service type                     : digital television
==================================


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