[FFmpeg-trac] #1766(undetermined:new): Can't encode MPEG-2 at more than ~3Mb/s

[FFmpeg]

#1766: Can't encode MPEG-2 at more than ~3Mb/s
-------------------------------------+-------------------------------------
             Reporter:  Agustín      |                    Owner:  (none)
  Dall'Alba                          |
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  git-master   |               Resolution:
             Keywords:  mpeg2video   |               Blocked By:
  dvd                                |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Comment (by Agustín Dall'Alba):

 Thank you for reading my old bug report. Surprisingly I can still
 reproduce this on ffmpeg n4.4 with libavcodec 58.134.100!

 I don't understand why mpeg2video does not allocate more bits to preserve
 the film grain even when set at the maximum quality:

 {{{ ffmpeg -i Sherlock\ S01E01\ sample.mkv -c:v mpeg2video -s 720x576 -q:v
 1 -an test2.mkv }}}

 Even with -q 1 it still has visible banding and blocking where there was
 none in the source. Thinking maybe the scaler was to blame, I tried with
 other codecs:

 {{{
 ffmpeg -i Sherlock\ S01E01\ sample.mkv -c:v mjpeg -s 720x576 -q:v 1 -an
 testj.mkv
 ffmpeg -i Sherlock\ S01E01\ sample.mkv -c:v mpeg1video -s 720x576 -q:v 1
 -an test1.mkv
 ffmpeg -i Sherlock\ S01E01\ sample.mkv -c:v mpeg4 -s 720x576 -q:v 1 -an
 test4.mkv
 ffmpeg -i Sherlock\ S01E01\ sample.mkv -c:v libxvid -s 720x576 -q:v 1 -an
 testx.mkv
 ffmpeg -i Sherlock\ S01E01\ sample.mkv -c:v libx264 -s 720x576 -crf 1
 testh.mkv
 }}}

 mjpeg, mpeg1, mpeg2,and mpeg4 had the banding and blocking, but
 surprisingly libxvid made a file 5× larger that looked great and preserved
 the noise, even though it's the same format that mpeg4. libx264 also had
 no trouble. So perhaps there's something wrong a quantizer that's shared
 between all the internal mpeg* codecs?

 Anyway, I no longer use these codecs for anything, so if you're not
 interested in looking more into this you might as well close it wontfix.

 Cheers
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/1766#comment:9>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker