[FFmpeg-trac] #1137(avformat:open): adher to start media time in QuickTime edts/elst

[FFmpeg]

#1137: adher to start media time in QuickTime edts/elst
-------------------------------------+------------------------------------
             Reporter:  dericed      |                    Owner:
                 Type:  enhancement  |                   Status:  open
             Priority:  wish         |                Component:  avformat
              Version:  git-master   |               Resolution:
             Keywords:  mov edts     |               Blocked By:
             Blocking:               |  Reproduced by developer:  1
Analyzed by developer:  0            |
-------------------------------------+------------------------------------

Comment (by dericed):

 I added a new sample file created with:
 {{{
 ffmpeg -f lavfi -i mandelbrot -t 5 -pix_fmt yuv420p -timecode
 "01:00:00:00" 5seconds_with_tc.mov
 }}}

 Then resulting file is 5 seconds with a timecode track that goes from
 01:00:00:00 to 01:00:04:24.
 I then opened 5seconds_with_tc.mov in QuickTime 7, edit the file, and then
 saved it by hitting File>Save rather than File>"Save As" (whereas as "Save
 As" would remux the file via QuickTime, hitting only "Save" will relabel
 the existing 'moov' atom as 'free' and then append a new 'moov' atom to
 the file). The resulting file after the edit and save is named
 5seconds_with_tc_with_QTedit.mov and in QuickTime shows a timecode track
 that goes from 01:00:02:00 to 01:00:03:24.

 When I analyze the two files with ffmpeg I get:

 {{{
 ffmpeg -i 5seconds_with_tc.mov -i 5seconds_with_tc_with_QTedit.mov
 ffmpeg version 1.0.git Copyright (c) 2000-2013 the FFmpeg developers
   built on Jan  1 2013 20:04:43 with Apple clang version 4.1
 (tags/Apple/clang-421.11.66) (based on LLVM 3.1svn)
   configuration: --prefix=/usr/local/Cellar/ffmpeg/HEAD --enable-shared
 --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables
 --cc=cc --host-cflags= --host-ldflags= --enable-libx264 --enable-libfaac
 --enable-libmp3lame --enable-libxvid --enable-ffplay --enable-libopenjpeg
 --extra-cflags='-I/usr/local/Cellar/openjpeg/1.5.1/include/openjpeg-1.5 '
   libavutil      52. 13.100 / 52. 13.100
   libavcodec     54. 85.100 / 54. 85.100
   libavformat    54. 59.100 / 54. 59.100
   libavdevice    54.  3.102 / 54.  3.102
   libavfilter     3. 30.102 /  3. 30.102
   libswscale      2.  1.103 /  2.  1.103
   libswresample   0. 17.102 /  0. 17.102
   libpostproc    52.  2.100 / 52.  2.100
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '5seconds_with_tc.mov':
   Metadata:
     major_brand     : qt
     minor_version   : 512
     compatible_brands: qt
     encoder         : Lavf54.59.100
   Duration: 00:00:05.00, start: 0.000000, bitrate: 2012 kb/s
     Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
 640x480 [SAR 1:1 DAR 4:3], 2007 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc
     Metadata:
       handler_name    : DataHandler
       timecode        : 01:00:00:00
     Stream #0:1(eng): Data: none (tmcd / 0x64636D74)
     Metadata:
       handler_name    : DataHandler
       timecode        : 01:00:00:00
 Input #1, mov,mp4,m4a,3gp,3g2,mj2, from
 '5seconds_with_tc_with_QTedit.mov':
   Metadata:
     major_brand     : qt
     minor_version   : 512
     compatible_brands: qt
     encoder         : Lavf54.59.100
   Duration: 00:00:02.00, start: -2.000000, bitrate: 5044 kb/s
     Stream #1:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
 640x480 [SAR 1:1 DAR 4:3], 2007 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc
     Metadata:
       handler_name    : Apple Alias Data Handler
       timecode        : 01:00:00:00
     Stream #1:1(eng): Data: none (tmcd / 0x64636D74)
     Metadata:
       handler_name    : Apple Alias Data Handler
       timecode        : 01:00:00:00
 At least one output file must be specified
 }}}

 Both files show a timecode value of "01:00:00:00". ffplay and ffmpeg
 decoding of 5seconds_with_tc_with_QTedit.mov will use all 5 seconds of the
 file although QuickTime will only present the 2 seconds that were left
 after the editing.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1137#comment:3>
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