[FFmpeg-trac] #6307(undetermined:new): detected tbr different past 3.1.7 (1080i H.264)
FFmpeg
trac at avcodec.org
Tue Apr 11 21:24:39 EEST 2017
#6307: detected tbr different past 3.1.7 (1080i H.264)
-------------------------------------+-------------------------------------
Reporter: korylprince | Type: defect
Status: new | Priority: normal
Component: | Version:
undetermined | unspecified
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
The tbr of a 1080i H.264 clip is detected differently with versions 3.1.7
and early detecting '''29.97 tbr''' (which should be correct) and versions
after 3.1.7 (I've tested 3.2, 3.2.4, and current 3.3-dev) detecting
'''59.94 tbr'''.
I don't want to say either is wrong, because I don't know what the correct
answer is; The behavior is definitely different. I don't know exactly how
interlaced video works, but the fps should be 29.97 for this clip.
The clip in question is recorded from a Panasonic HDC-TM700.
This was discovered because newer versions of blender (including 3.2+
versions of ffmpeg) detect the given clip at 59.94 fps instead of 29.97
fps, meaning the video is imported twice as long as the audio. The bug
report is here: https://developer.blender.org/T51153
I am attaching logs for versions 3.1.7, 3.2, 3.2.4, and 3.3-dev (commit
efa89a8), and the clip used, 1080i_29.97.mts .
Command used:
{{{
ffprobe -v 9 -loglevel 99 -report 1080i_29.97.mts
}}}
Here is the relevant output from each ffprobe command:
3.1.7:
{{{
Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p,
1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
}}}
3.2:
{{{
Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p(top
first), 1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 59.94 tbr, 90k tbn, 59.94
tbc
}}}
3.2.4:
{{{
Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p(top
first), 1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 59.94 tbr, 90k tbn, 59.94
tbc
}}}
3.3-dev:
{{{
Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p(top
first), 1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 59.94 tbr, 90k tbn, 59.94
tbc
}}}
As you can see, 3.1.7 has 29.97 tbr, and the reset are identical and 59.94
tbr. My guess is this is incorrect, and it should be detected as 29.97
tbr.
I think the problem is in libavformat judging from the comments on the
blender bug.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/6307>
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