Transcoded audio not delivered until fully transcoded

[Will Lunniss]

I and a number of ServiiGo users have noticed a problem whereby certain files when transcoded are not delived by the webserver until they have been fully transcoded. This seems to affect m4a files from iTunes, as well as certain flac files, possibly more. This problem is reproducible in MediaBrowser as well as ServiiGo. If you try to play back on of the files in MediaBrowesr, you will see ffmpeg transcoding the file and the file size increasing, and then once the file is fully transcoded, ffmpeg will stop and the webserver will return the file.

Attached is a sample flac file that a user sent in.

[Petr Nejedly]

This seems to be caused by the cover image being transcoded as a part of the job (as implemented by #650). When I use -vn it works.

d:\sample_media\music\test>d:\sample_media\video\ffmpeg.exe -i "01. Gil Shaham, Philharmonia Orchest
ra (Sinopoli) - Bruch VC 1 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca.flac" -c:a libmp
3lame -f mp3 d:\out.mp3
ffmpeg version 2.4.git Copyright (c) 2000-2014 the FFmpeg developers
  built on Nov 19 2014 22:12:09 with gcc 4.7.2 (GCC)
  configuration: --enable-static --disable-shared --disable-ffplay --disable-ffserver --enable-memal
ign-hack --enable-libmp3lame --enable-libass --enable-librtmp --enable-fontconfig --enable-libfreety
pe --enable-zlib --enable-libx264 --enable-libspeex --extra-libs='-lrtmp -lpolarssl -lws2_32 -lwinmm
 -lexpat -lfreetype -lfribidi -lz' --arch=x86 --enable-runtime-cpudetect --enable-pthreads --target-
os=mingw32 --cross-prefix=i686-w64-mingw32- --enable-gpl --pkg-config=pkg-config
  libavutil      54. 14.100 / 54. 14.100
  libavcodec     56. 12.101 / 56. 12.101
  libavformat    56. 14.100 / 56. 14.100
  libavdevice    56.  3.100 / 56.  3.100
  libavfilter     5.  2.103 /  5.  2.103
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
Input #0, flac, from '01. Gil Shaham, Philharmonia Orchestra (Sinopoli) - Bruch VC 1 in G minor Op.
26 I. Vorspiel. Allegro moderato - attaca.flac':
  Metadata:
    ARTIST          : Gil Shaham, Philharmonia Orchestra (Sinopoli);Gil Shaham, Philharmonia Orchest
ra (Sinopoli)
    encoder         : FLAC.EXE -6 -V -T "ARTIST=Gil Shaham, Philharmonia Orchestra (Sinopoli)" -T "T
ITLE=Bruch VC 1 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca" -T "ALBUM=Mendelssohn - Br
uch - Violin Concertos" -T "DATE=" -T "TRACKNUMBER=01" -T "GENRE=Classical" -
    TITLE           : Bruch VC 1 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca;Bruch VC 1
 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca
    GENRE           : Classical;Classical
    TLEN            : 517706
    track           : 01
    encoded_by      : Exact Audio Copy   (Secure mode)
    ALBUM           : Mendelssohn - Bruch - Violin Concertos;Mendelssohn - Bruch - Violin Concertos
    disc            : 1
    TOTALDISCS      : 1
    TOTALTRACKS     : 6
  Duration: 00:08:37.71, start: 0.000000, bitrate: 635 kb/s
    Stream #0:0: Audio: flac, 44100 Hz, stereo, s16
    Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 600x600 [SAR 1:1 DAR 1:1], 90k
 tbr, 90k tbn, 90k tbc
    Metadata:
      comment         : Cover (front)
[swscaler @ 04270060] deprecated pixel format used, make sure you did set range correctly
[mp3 @ 04309580] Frame rate very high for a muxer not efficiently supporting it.
Please consider specifying a lower framerate, a different muxer or -vsync 2
Output #0, mp3, to 'd:\out.mp3':
  Metadata:
    TPE1            : Gil Shaham, Philharmonia Orchestra (Sinopoli);Gil Shaham, Philharmonia Orchest
ra (Sinopoli)
    TOTALTRACKS     : 6
    TIT2            : Bruch VC 1 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca;Bruch VC 1
 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca
    TCON            : Classical;Classical
    TLEN            : 517706
    TRCK            : 01
    TENC            : Exact Audio Copy   (Secure mode)
    TALB            : Mendelssohn - Bruch - Violin Concertos;Mendelssohn - Bruch - Violin Concertos
    TPOS            : 1
    TOTALDISCS      : 1
    TSSE            : Lavf56.14.100
    Stream #0:0: Video: png, rgb24, 600x600 [SAR 1:1 DAR 1:1], q=2-31, 200 kb/s, 90k fps, 90k tbn, 9
0k tbc
    Metadata:
      comment         : Cover (front)
      encoder         : Lavc56.12.101 png
    Stream #0:1: Audio: mp3 (libmp3lame), 44100 Hz, stereo, s16p
    Metadata:
      encoder         : Lavc56.12.101 libmp3lame
Stream mapping:
  Stream #0:1 -> #0:0 (mjpeg (native) -> png (native))
  Stream #0:0 -> #0:1 (flac (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
frame=    1 fps=0.0 q=0.0 Lsize=    8596kB time=00:08:37.72 bitrate= 136.0kbits/s
video:505kB audio:8090kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.008908
%

vs

d:\sample_media\music\test>d:\sample_media\video\ffmpeg.exe -i "01. Gil Shaham, Philharmonia Orchest
ra (Sinopoli) - Bruch VC 1 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca.flac" -c:a libmp
3lame -vn -f mp3 d:\out.mp3
ffmpeg version 2.4.git Copyright (c) 2000-2014 the FFmpeg developers
  built on Nov 19 2014 22:12:09 with gcc 4.7.2 (GCC)
  configuration: --enable-static --disable-shared --disable-ffplay --disable-ffserver --enable-memal
ign-hack --enable-libmp3lame --enable-libass --enable-librtmp --enable-fontconfig --enable-libfreety
pe --enable-zlib --enable-libx264 --enable-libspeex --extra-libs='-lrtmp -lpolarssl -lws2_32 -lwinmm
 -lexpat -lfreetype -lfribidi -lz' --arch=x86 --enable-runtime-cpudetect --enable-pthreads --target-
os=mingw32 --cross-prefix=i686-w64-mingw32- --enable-gpl --pkg-config=pkg-config
  libavutil      54. 14.100 / 54. 14.100
  libavcodec     56. 12.101 / 56. 12.101
  libavformat    56. 14.100 / 56. 14.100
  libavdevice    56.  3.100 / 56.  3.100
  libavfilter     5.  2.103 /  5.  2.103
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
Input #0, flac, from '01. Gil Shaham, Philharmonia Orchestra (Sinopoli) - Bruch VC 1 in G minor Op.
26 I. Vorspiel. Allegro moderato - attaca.flac':
  Metadata:
    ARTIST          : Gil Shaham, Philharmonia Orchestra (Sinopoli);Gil Shaham, Philharmonia Orchest
ra (Sinopoli)
    encoder         : FLAC.EXE -6 -V -T "ARTIST=Gil Shaham, Philharmonia Orchestra (Sinopoli)" -T "T
ITLE=Bruch VC 1 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca" -T "ALBUM=Mendelssohn - Br
uch - Violin Concertos" -T "DATE=" -T "TRACKNUMBER=01" -T "GENRE=Classical" -
    TITLE           : Bruch VC 1 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca;Bruch VC 1
 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca
    GENRE           : Classical;Classical
    TLEN            : 517706
    track           : 01
    encoded_by      : Exact Audio Copy   (Secure mode)
    ALBUM           : Mendelssohn - Bruch - Violin Concertos;Mendelssohn - Bruch - Violin Concertos
    disc            : 1
    TOTALDISCS      : 1
    TOTALTRACKS     : 6
  Duration: 00:08:37.71, start: 0.000000, bitrate: 635 kb/s
    Stream #0:0: Audio: flac, 44100 Hz, stereo, s16
    Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 600x600 [SAR 1:1 DAR 1:1], 90k
 tbr, 90k tbn, 90k tbc
    Metadata:
      comment         : Cover (front)
File 'd:\out.mp3' already exists. Overwrite ? [y/N] y
Output #0, mp3, to 'd:\out.mp3':
  Metadata:
    TPE1            : Gil Shaham, Philharmonia Orchestra (Sinopoli);Gil Shaham, Philharmonia Orchest
ra (Sinopoli)
    TOTALTRACKS     : 6
    TIT2            : Bruch VC 1 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca;Bruch VC 1
 in G minor Op. 26 I. Vorspiel. Allegro moderato - attaca
    TCON            : Classical;Classical
    TLEN            : 517706
    TRCK            : 01
    TENC            : Exact Audio Copy   (Secure mode)
    TALB            : Mendelssohn - Bruch - Violin Concertos;Mendelssohn - Bruch - Violin Concertos
    TPOS            : 1
    TOTALDISCS      : 1
    TSSE            : Lavf56.14.100
    Stream #0:0: Audio: mp3 (libmp3lame), 44100 Hz, stereo, s16p
    Metadata:
      encoder         : Lavc56.12.101 libmp3lame
Stream mapping:
  Stream #0:0 -> #0:0 (flac (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
size=    8091kB time=00:08:37.72 bitrate= 128.0kbits/s
video:0kB audio:8090kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.009186%

Note the FFmpeg progress line (eg frame 1)

[Former user]

Could the cover art be extracted and stored at the library scan stage, and "-vn" used on playback?

[Will Lunniss]

@grolschie No the point is to ensure the transcoded file contains the original metadata and artwork embedded in it so that it can be extracted by clients. E.g. in ServiiGo I extract the high res artwork to display in the no playing screen/lockscreen. It also means the cached files can be used by third party players in offline mode.

@zip So are you checking the frame progress before delivering the content, or is ffmpeg blocking? Anyway to work around it?

[Petr Nejedly]

Looks like FFmpeg blocks somehow.

i will see if there are any flags i could use.

[Petr Nejedly]

looks like "-c:v copy" does the trick

[Will Lunniss]

Great, thanks!