[FFmpeg-trac] #4944(documentation:new): -r output option misguiding documentation
FFmpeg
trac at avcodec.org
Mon Oct 19 15:34:03 CEST 2015
#4944: -r output option misguiding documentation
-------------------------------------+-------------------------------------
Reporter: basinilya | Type: defect
Status: new | Priority: normal
Component: | Version:
documentation | unspecified
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Summary of the bug:
{{{
doc/ffmpeg.texi:As an output option, duplicate or drop input frames to
achieve constant output
}}}
In fact, that sounds more like the description of the fps filter. What
'-r' option actually does, is set the declared fps of a video stream
without actually duplicating frames (it may drop frames though).
The following example produces a 2-second 4fps video and uses '-r 120'.
The demuxer says: '120 fps', but prints only 8 frames with proper PTS.
{{{
$ ffmpeg -y -f lavfi -i testsrc=s=720x576:r=4:d=2 -r 120 -pix_fmt yuv422p
-vcodec rawvideo -f matroska - 2>/dev/null | ffmpeg -f matroska -i - -vf
"showinfo" -f null x
ffmpeg version N-72058-g3ecc063 Copyright (c) 2000-2015 the FFmpeg
developers
built with gcc 4.9.2 (GCC)
configuration: --disable-static --enable-shared --enable-gpl --enable-
version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-
fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass
--enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec
--enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc
--enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-
librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex
--enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-
aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx
--enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265
--enable-libxavs --enable-libxvid --enable-lzma --enable-decklink
--enable-zlib
libavutil 54. 23.101 / 54. 23.101
libavcodec 56. 38.100 / 56. 38.100
libavformat 56. 33.100 / 56. 33.100
libavdevice 56. 4.100 / 56. 4.100
libavfilter 5. 16.101 / 5. 16.101
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 3.100 / 53. 3.100
Input #0, matroska,webm, from 'pipe:':
Metadata:
ENCODER : Lavf56.33.100
Duration: N/A, start: 0.000000, bitrate: N/A
Stream #0:0: Video: rawvideo (Y42B / 0x42323459), yuv422p, 720x576,
SAR 1:1 DAR 5:4, 120 fps, 120 tbr, 1k tbn, 1k tbc (default)
Metadata:
ENCODER : Lavc56.38.100 rawvideo
[Parsed_showinfo_0 @ 0000000002a03f20] config in time_base: 1/1000,
frame_rate: 120/1
[Parsed_showinfo_0 @ 0000000002a03f20] config out time_base: 0/0,
frame_rate: 0/0
Output #0, null, to 'x':
Metadata:
encoder : Lavf56.33.100
Stream #0:0: Video: rawvideo (Y42B / 0x42323459), yuv422p, 720x576
[SAR 1:1 DAR 5:4], q=2-31, 200 kb/s, 120 fps, 120 tbn, 120 tbc (default)
Metadata:
encoder : Lavc56.38.100 rawvideo
Stream mapping:
Stream #0:0 -> #0:0 (rawvideo (native) -> rawvideo (native))
[Parsed_showinfo_0 @ 0000000002a03f20] n: 0 pts: 0 pts_time:0
pos: 618 fmt:yuv422p sar:1/1 s:720x576 i:P iskey:1 type:I
checksum:8B0AA2CB plane_checksum:[87271B24 F6292B83 9D3A5C24] mean:[126
129 126] stdev:[71.4 70.2 72.6]
[null @ 0000000002a02be0] Encoder did not produce proper pts, making some
up.
[Parsed_showinfo_0 @ 0000000002a03f20] n: 1 pts: 250 pts_time:0.25
pos: 830081 fmt:yuv422p sar:1/1 s:720x576 i:P iskey:1 type:I
checksum:5C15AB10 plane_checksum:[C538A9E0 3585795C 479987C5] mean:[126
129 126] stdev:[71.4 70.2 72.7]
[Parsed_showinfo_0 @ 0000000002a03f20] n: 2 pts: 500 pts_time:0.5
pos: 1659545 fmt:yuv422p sar:1/1 s:720x576 i:P iskey:1 type:I
checksum:B10C5D37 plane_checksum:[9A6BC88B 93E6BB84 18B8D90A] mean:[126
129 126] stdev:[71.4 70.1 72.8]
[Parsed_showinfo_0 @ 0000000002a03f20] n: 3 pts: 750 pts_time:0.75
pos: 2489009 fmt:yuv422p sar:1/1 s:720x576 i:P iskey:1 type:I
checksum:8D290D16 plane_checksum:[F3FAE338 28B7FC3F AEDA2D81] mean:[125
129 126] stdev:[71.4 70.0 72.9]
[Parsed_showinfo_0 @ 0000000002a03f20] n: 4 pts: 1000 pts_time:1
pos: 3318473 fmt:yuv422p sar:1/1 s:720x576 i:P iskey:1 type:I
checksum:11BC56BD plane_checksum:[B4839897 9F273F08 9A537F0F] mean:[124
129 126] stdev:[71.3 69.9 72.9]
[Parsed_showinfo_0 @ 0000000002a03f20] n: 5 pts: 1250 pts_time:1.25
pos: 4147937 fmt:yuv422p sar:1/1 s:720x576 i:P iskey:1 type:I
checksum:1A09A329 plane_checksum:[ADA1817E F1454629 5FF1DB73] mean:[124
129 126] stdev:[71.2 69.9 73.0]
[Parsed_showinfo_0 @ 0000000002a03f20] n: 6 pts: 1500 pts_time:1.5
pos: 4977401 fmt:yuv422p sar:1/1 s:720x576 i:P iskey:1 type:I
checksum:F5CF596F plane_checksum:[27E9F6FA 831823A8 7D483EBE] mean:[124
129 126] stdev:[71.3 70.0 73.0]
[Parsed_showinfo_0 @ 0000000002a03f20] n: 7 pts: 1750 pts_time:1.75
pos: 5806865 fmt:yuv422p sar:1/1 s:720x576 i:P iskey:1 type:I
checksum:22CD0DB6 plane_checksum:[816D6A3D 14230294 6028A0D6] mean:[125
129 127] stdev:[71.4 70.0 72.9]
frame= 8 fps=0.0 q=0.0 Lsize=N/A time=00:00:01.75 bitrate=N/A
video:1kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: unknown
}}}
Please fix the doc.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/4944>
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