[FFmpeg-trac] #398(avfilter:new): ffplay does not initialize dar/sar for scale filter

[FFmpeg]

#398: ffplay does not initialize dar/sar for scale filter
------------------------+-------------------------
 Reporter:  rectalogic  |        Type:  defect
   Status:  new         |    Priority:  normal
Component:  avfilter    |     Version:  git-master
 Keywords:              |  Blocked By:
 Blocking:              |  Reproduced:  0
 Analyzed:  0           |
------------------------+-------------------------
 The 'sar' and 'dar' expressions available in the scale filter are not
 initialized properly in ffplay. I have a sample video sar43.mpg (download
 from http://www.box.net/shared/jdtkdlhsvres106e157z) that is 1440x1080
 with SAR of 4:3 and so DAR of 16:9. When the scale filter expression is
 parsed, 'sar' is 1 and 'dar' is 1.333 (4:3) because
 inlink->sample_aspect_ratio is {0,1} instead of {4,3}.

 gdb info from breakpoint in libavfilter/vf_scale.c:config_props()
 {{{
 (gdb) p var_values[VAR_SAR]
 $32 = 1
 (gdb) p var_values[VAR_DAR]
 $33 = 1.3333333730697632
 (gdb) p inlink->sample_aspect_ratio
 $34 = {num = 0, den = 1}
 }}}
 ffplay output:
 {{{
 $ ./ffplay -vf scale=600*dar:600 /storage/test/mencoder/sar43.mpg
 ffplay version N-31895-gee5234d, Copyright (c) 2003-2011 the FFmpeg
 developers
   built on Aug 14 2011 23:40:42 with gcc 4.4.3
   configuration: --enable-debug=gdb3 --disable-optimizations --disable-asm
 --disable-stripping
   libavutil    51. 12. 0 / 51. 12. 0
   libavcodec   53. 10. 0 / 53. 10. 0
   libavformat  53.  7. 0 / 53.  7. 0
   libavdevice  53.  3. 0 / 53.  3. 0
   libavfilter   2. 31. 1 /  2. 31. 1
   libswscale    2.  0. 0 /  2.  0. 0
 Input #0, mpeg, from '/storage/test/mencoder/sar43.mpg':
   Duration: 00:00:03.06, start: 0.157667, bitrate: 27326 kb/s
     Stream #0.0[0x1e0]: Video: mpeg2video (Main), yuv420p, 1440x1080 [SAR
 4:3 DAR 16:9], 28000 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
     Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, stereo, s16, 384 kb/s
 [scale @ 0x2897e60] w:1440 h:1080 fmt:yuv420p -> w:800 h:600 fmt:yuv420p
 flags:0x4
 }}}
 I think ffplay needs to insert a 'buffer' filter before 'scale' like
 ffmpeg does?

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/398>
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