[FFmpeg-trac] #3990(ffmpeg:new): Video duration increases when reducing frame rate
FFmpeg
trac at avcodec.org
Tue Sep 30 09:52:28 CEST 2014
#3990: Video duration increases when reducing frame rate
--------------------------------+--------------------------------------
Reporter: t.rapp | Type: defect
Status: new | Priority: normal
Component: ffmpeg | Version: git-master
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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When reducing the frame rate of a 25Hz/20sec AVI/HuffYUV video test file
to 1Hz the duration increases to 22sec.
Comparing the framemd5 output of input file and output file (see
attachments) it seems that the first two frames of the input file are
passed through, then each frame at the middle of the output interval is
passed (frame 13 for the first 1sec interval, frame 38 for the second 1sec
interval, ...).
How to reproduce:
{{{
# create 25Hz test input file
% ffmpeg -f lavfi -graph "testsrc=size=pal:rate=25 [out0]" -i dummy \
-f avi -codec:v huffyuv -pix_fmt yuv422p -t 20 /tmp/test-25hz.avi
# create 1Hz test output file
% ffmpeg -i /tmp/test-25hz.avi -f avi -codec:v huffyuv -r 1 /tmp/test-
1hz.avi
ffmpeg version N-66544-g61c0683 Copyright (c) 2000-2014 the FFmpeg
developers
built on Sep 30 2014 09:02:33 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
configuration: --cc='ccache gcc' --enable-debug --enable-version3
libavutil 54. 7.101 / 54. 7.101
libavcodec 56. 1.101 / 56. 1.101
libavformat 56. 7.101 / 56. 7.101
libavdevice 56. 1.100 / 56. 1.100
libavfilter 5. 1.102 / 5. 1.102
libswscale 3. 1.100 / 3. 1.100
libswresample 1. 1.100 / 1. 1.100
Input #0, avi, from '/tmp/test-25hz.avi':
Metadata:
encoder : Lavf56.7.101
Duration: 00:00:20.00, start: 0.000000, bitrate: 46859 kb/s
Stream #0:0: Video: huffyuv (HFYU / 0x55594648), yuv422p, 720x576,
46945 kb/s, SAR 1:1 DAR 5:4, 25 fps, 25 tbr, 25 tbn, 25 tbc
[huffyuv @ 0x1be5a20] using huffyuv 2.2.0 or newer interlacing flag
Output #0, avi, to '/tmp/test02-1hz.avi':
Metadata:
ISFT : Lavf56.7.101
Stream #0:0: Video: huffyuv (HFYU / 0x55594648), yuv422p, 720x576 [SAR
1:1 DAR 5:4], q=2-31, 200 kb/s, 1 fps, 1 tbn, 1 tbc
Metadata:
encoder : Lavc56.1.101 huffyuv
Stream mapping:
Stream #0:0 -> #0:0 (huffyuv (native) -> huffyuv (native))
Press [q] to stop, [?] for help
frame= 22 fps= 13 q=0.0 Lsize= 5040kB time=00:00:22.00
bitrate=1876.8kbits/s dup=0 drop=478
video:5034kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 0.124002%
}}}
--
Ticket URL: <https://trac.ffmpeg.org/ticket/3990>
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