#5761: GOP inconsistencies when transcoding H.264 to MPEG2 MXF
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Reporter: edob | Type: defect
Status: new | Priority: normal
Component: undetermined | Version: 3.0.2
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Hi,
here's my summary of the bug:
When transcoding H.264 video files from a GoPro Hero3
(1920x1080,25fps,[email protected],30Mbps VBR,CABAC, M=1,N=13) to XDCAM
HD422-Style MPEG2 video (50Mbps CBR, 1080i25, M=3,N=12), one seems to only
get proper files if t<=60.00 seconds, but if t>60 seconds, the GOPs of the
output file are of variable length (always multiples of M). I've
encountered similar behaviour with other H.264 files as well, but this one
is easier to reproduce (because it's not "some file from some guy").
[ Src file can be supplied but is 230M. ]
How to reproduce:
{{{
% ffmpeg -i C:\FFMPEG\GOPR_61sec.mp4 -vcodec mpeg2video -b:v 50M -minrate
50M -maxrate 50M -g 12 -bf 2 -vf colormatrix=bt601:bt709 -color_primaries
bt709 -color_trc bt709 -colorspace bt709 -flags +ildct+ilme -top 1 -s
1920x1080 -r 25.000 -pix_fmt yuv422p -acodec pcm_s24le -ar 48000
-filter_complex "[0:a]channelsplit=channel_layout=stereo[a1][a2]" -map
0:v:0 -map "[a1]" -map "[a2]" C:\FFMPEG\GOPR_Test.mxf
ffmpeg version N-81306-g26695ae
built on 08/08/16 (Win32 static by zeranoe)
}}}
Please let me know if you need more detail.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/5761>
FFmpeg <https://ffmpeg.org>
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