[FFmpeg-user] volumedetect filter and possible bug with -ss -t

Sub Phil phil4000n at gmail.com
Sun Sep 4 16:17:32 EEST 2016


Hi,

I wish to have an histogram of portion of an audio file, however the
seeking (-ss) and cut (-t) operator provide very different histogram
results.

Quid re-opening of bug 1727?

These are my CLI with -ss before -i
ffmpeg -ss 17401 -t 2 -i "20160903 1 oreiller fin 8h08.3gp" -af
volumedetect -f null - > histogram17401_front.txt 2>&1

ffmpeg -ss 17401 -i "20160903 1 oreiller fin 8h08.3gp" -t 2 -af
volumedetect -f null - > histogram17401_ss_before_i_n_t_after_i.txt 2>&1

ffmpeg -ss 17401 -i "20160903 1 oreiller fin 8h08.3gp" -af volumedetect -t
2 -f null - > histogram17401_ss_before_in_t_after_voldetect.txt 2>&1

These are my CLI with -ss After -i
ffmpeg -i "20160903 1 oreiller fin 8h08.3gp" -ss 17401 -t 2 -af
volumedetect -f null - > histogram17401_after_i.txt 2>&1

ffmpeg -i "20160903 1 oreiller fin 8h08.3gp" -af volumedetect -ss 17401 -t
2 -f null - > histogram17401_after_voldetect.txt 2>&1


Console output below.

Note: the following are different
ffmpeg -ss 17401 -t 2 -y -i "20160903 1 oreiller fin 8h08.3gp" -c:a copy
front.3gp
file duration: 4h44 53sec

ffmpeg -ss 17401 -y -i "20160903 1 oreiller fin 8h08.3gp" -t 2 -c:a copy
front_t_after.3gp
file duration: 2sec

ffmpeg -y -i "20160903 1 oreiller fin 8h08.3gp" -ss 17401 -t 2 -c:a copy
after.3gp
file duration: 2sec


RE:
https://trac.ffmpeg.org/wiki/Seeking
https://trac.ffmpeg.org/ticket/1727




ffmpeg -ss 17401 -t 2 -i "20160903 1 oreiller fin 8h08.3gp" -af
volumedetect -f null - > histogram17401_front.txt 2>&1
ffmpeg version 2.8.4 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 5.2.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads
--enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r
--enable-gnutls --enable-iconv --enable-libass --enable-libbluray
--enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype
--enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug
--enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb
--enable-libopenjpeg --enable-libopus --enable-librtmp
--enable-libschroedinger --enable-libsoxr --enable-libspeex
--enable-libtheora --enable-libtwolame --enable-libvidstab
--enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis
--enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264
--enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma
--enable-decklink --enable-zlib
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '20160903 1 oreiller fin 8h08.3gp':
  Metadata:
    major_brand     : 3gp4
    minor_version   : 0
    compatible_brands: isom3gp4
    creation_time   : 2016-09-04 06:08:38
  Duration: 09:34:54.02, start: 0.000000, bitrate: 23 kb/s
    Stream #0:0(eng): Audio: amr_wb (sawb / 0x62776173), 16000 Hz, mono,
flt, 23 kb/s (default)
    Metadata:
      creation_time   : 2016-09-04 06:08:38
      handler_name    : SoundHandle
Output #0, null, to 'pipe:':
  Metadata:
    major_brand     : 3gp4
    minor_version   : 0
    compatible_brands: isom3gp4
    encoder         : Lavf56.40.101
    Stream #0:0(eng): Audio: pcm_s16le, 16000 Hz, mono, s16, 256 kb/s
(default)
    Metadata:
      creation_time   : 2016-09-04 06:08:38
      handler_name    : SoundHandle
      encoder         : Lavc56.60.100 pcm_s16le
Stream mapping:
  Stream #0:0 -> #0:0 (amr_wb (amrwb) -> pcm_s16le (native))
Press [q] to stop, [?] for help
size=N/A time=00:00:02.00 bitrate=N/A
video:0kB audio:62kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: unknown
[Parsed_volumedetect_0 @ 02ede740] n_samples: 32000
[Parsed_volumedetect_0 @ 02ede740] mean_volume: -40.4 dB
[Parsed_volumedetect_0 @ 02ede740] max_volume: -22.7 dB
[Parsed_volumedetect_0 @ 02ede740] histogram_22db: 1
[Parsed_volumedetect_0 @ 02ede740] histogram_23db: 2
[Parsed_volumedetect_0 @ 02ede740] histogram_24db: 4
[Parsed_volumedetect_0 @ 02ede740] histogram_25db: 2
[Parsed_volumedetect_0 @ 02ede740] histogram_26db: 21
[Parsed_volumedetect_0 @ 02ede740] histogram_27db: 27












ffmpeg -i "20160903 1 oreiller fin 8h08.3gp" -ss 17401 -t 2 -af
volumedetect -f null - > histogram17401_after_i.txt 2>&1
ffmpeg version 2.8.4 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 5.2.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads
--enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r
--enable-gnutls --enable-iconv --enable-libass --enable-libbluray
--enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype
--enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug
--enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb
--enable-libopenjpeg --enable-libopus --enable-librtmp
--enable-libschroedinger --enable-libsoxr --enable-libspeex
--enable-libtheora --enable-libtwolame --enable-libvidstab
--enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis
--enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264
--enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma
--enable-decklink --enable-zlib
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '20160903 1 oreiller fin 8h08.3gp':
  Metadata:
    major_brand     : 3gp4
    minor_version   : 0
    compatible_brands: isom3gp4
    creation_time   : 2016-09-04 06:08:38
  Duration: 09:34:54.02, start: 0.000000, bitrate: 23 kb/s
    Stream #0:0(eng): Audio: amr_wb (sawb / 0x62776173), 16000 Hz, mono,
flt, 23 kb/s (default)
    Metadata:
      creation_time   : 2016-09-04 06:08:38
      handler_name    : SoundHandle
Output #0, null, to 'pipe:':
  Metadata:
    major_brand     : 3gp4
    minor_version   : 0
    compatible_brands: isom3gp4
    encoder         : Lavf56.40.101
    Stream #0:0(eng): Audio: pcm_s16le, 16000 Hz, mono, s16, 256 kb/s
(default)
    Metadata:
      creation_time   : 2016-09-04 06:08:38
      handler_name    : SoundHandle
      encoder         : Lavc56.60.100 pcm_s16le
Stream mapping:
  Stream #0:0 -> #0:0 (amr_wb (amrwb) -> pcm_s16le (native))
Press [q] to stop, [?] for help
size=N/A time=00:00:00.00 bitrate=N/A
size=N/A time=00:00:00.00 bitrate=N/A
size=N/A time=00:00:00.00 bitrate=N/A
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size=N/A time=00:00:02.00 bitrate=N/A
video:0kB audio:62kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: unknown
[Parsed_volumedetect_0 @ 03008f60] n_samples: 278448320
[Parsed_volumedetect_0 @ 03008f60] mean_volume: -46.0 dB
[Parsed_volumedetect_0 @ 03008f60] max_volume: 0.0 dB
[Parsed_volumedetect_0 @ 03008f60] histogram_0db: 284
[Parsed_volumedetect_0 @ 03008f60] histogram_1db: 348
[Parsed_volumedetect_0 @ 03008f60] histogram_2db: 477
[Parsed_volumedetect_0 @ 03008f60] histogram_3db: 764
[Parsed_volumedetect_0 @ 03008f60] histogram_4db: 1067
[Parsed_volumedetect_0 @ 03008f60] histogram_5db: 1423
[Parsed_volumedetect_0 @ 03008f60] histogram_6db: 1907
[Parsed_volumedetect_0 @ 03008f60] histogram_7db: 2367
[Parsed_volumedetect_0 @ 03008f60] histogram_8db: 2789
[Parsed_volumedetect_0 @ 03008f60] histogram_9db: 3282
[Parsed_volumedetect_0 @ 03008f60] histogram_10db: 3826
[Parsed_volumedetect_0 @ 03008f60] histogram_11db: 4302
[Parsed_volumedetect_0 @ 03008f60] histogram_12db: 4822
[Parsed_volumedetect_0 @ 03008f60] histogram_13db: 5170
[Parsed_volumedetect_0 @ 03008f60] histogram_14db: 5621
[Parsed_volumedetect_0 @ 03008f60] histogram_15db: 5869
[Parsed_volumedetect_0 @ 03008f60] histogram_16db: 6426
[Parsed_volumedetect_0 @ 03008f60] histogram_17db: 6442
[Parsed_volumedetect_0 @ 03008f60] histogram_18db: 6645
[Parsed_volumedetect_0 @ 03008f60] histogram_19db: 6793
[Parsed_volumedetect_0 @ 03008f60] histogram_20db: 7029
[Parsed_volumedetect_0 @ 03008f60] histogram_21db: 7409
[Parsed_volumedetect_0 @ 03008f60] histogram_22db: 7564
[Parsed_volumedetect_0 @ 03008f60] histogram_23db: 7729
[Parsed_volumedetect_0 @ 03008f60] histogram_24db: 8126
[Parsed_volumedetect_0 @ 03008f60] histogram_25db: 8869
[Parsed_volumedetect_0 @ 03008f60] histogram_26db: 9874
[Parsed_volumedetect_0 @ 03008f60] histogram_27db: 11093
[Parsed_volumedetect_0 @ 03008f60] histogram_28db: 13918
[Parsed_volumedetect_0 @ 03008f60] histogram_29db: 17182
[Parsed_volumedetect_0 @ 03008f60] histogram_30db: 22943
[Parsed_volumedetect_0 @ 03008f60] histogram_31db: 30657
[Parsed_volumedetect_0 @ 03008f60] histogram_32db: 43931
[Parsed_volumedetect_0 @ 03008f60] histogram_33db: 62609


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