#404: Rounding error in scaling expression
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Reporter: blaw | Owner:
Type: defect | Status: new
Priority: normal | Component: undetermined
Version: git | Resolution:
Keywords: rouding scalling expression | Blocked By:
Blocking: | Reproduced: 0
Analyzed: 0 |
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Comment (by saste):
Unreproducible here with the command (you need git of the day for testing
it):
{{{
$ ffplay -f lavfi "testsrc=s=352x480:sar=20/11,scale=iw:ow/dar"
ffplay version N-32028-g34c9975, Copyright (c) 2003-2011 the FFmpeg
developers
built on Aug 21 2011 15:27:17 with gcc 4.4.5
configuration: --prefix=/home/stefano --enable-libx264 --enable-libxvid
--enable-librtmp --disable-shared --enable-static --enable-debug=3
--enable-pthreads --enable-libvorbis --enable-avfilter --enable-gpl
--enable-nonfree --enable-libmp3lame --enable-libtheora --enable-gpl
--enable-x11grab --enable-libschroedinger --enable-libopenjpeg --enable-
frei0r --enable-libopencv --disable-optimizations --disable-mmx --enable-
libfreetype
libavutil 51. 13. 0 / 51. 13. 0
libavcodec 53. 11. 0 / 53. 11. 0
libavformat 53. 9. 0 / 53. 9. 0
libavdevice 53. 3. 0 / 53. 3. 0
libavfilter 2. 34. 1 / 2. 34. 0
libswscale 2. 0. 0 / 2. 0. 0
libpostproc 51. 2. 0 / 51. 2. 0
[testsrc @ 0xa2c0790] size:352x480 rate:25/1 duration:-1.000000 sar:20/11
[scale @ 0xa28efe0] w:352 h:480 fmt:rgb24 -> w:352 h:264 fmt:yuv420p
flags:0x2
[lavfi @ 0xa2bf8a0] Estimating duration from bitrate, this may be
inaccurate
Input #0, lavfi, from 'testsrc=s=352x480:sar=20/11,scale=iw:ow/dar':
Duration: N/A, start: 0.000000, bitrate: N/A
Stream #0.0: Video: rawvideo, yuv420p, 352x264 [SAR 20:11 DAR 80:33],
25 tbr, 25 tbn, 25 tbc
5.32 A-V: 0.000 s:0.0 aq= 0KB vq= 817KB sq= 0B f=0/0 0/0
}}}
Please try and report, I guess it may be a platform-specific problem.
Even in this case, you can force the h value to be a multiple of the
chroma vertical subsampling value, for example by setting
scale=iw:floor(ow/dar/hsub)*hsub.
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/404#comment:1>
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