using -qscale in ffmpeg doesn't have any effect on coding

[Nido Media]

Binary package hint: ffmpeg

using ffmpeg comming with ubuntu jaunty (which is FFmpeg version
0.5=-svn17737+3:0.svn20090303-1ubuntu4); usage of the -qscale rather then -b
doesn't change the end result file size. In fact; coding a flv video five times
with qscale going from 1 to 5 has no effect; using 25 doesn't quite make the
video any smaller or less nice to watch.

Originally found this with trying to transcode vob mpeg to a theora; trying
-qmin, -qmax -sameq seems to have the same effect.

I guess the default of 200kb/s for the bitrate setting is taking precedence over
what's set for the quantizer

Here's some command line session which shows the problem. This isn't limited to vob -> flv; qscale doesn't work for theora->theora as well, (and probably a lot more, if not everything).

0 nido@toad:~/ for x in 1 2 3 4 5; do ffmpeg -y -i HARRY_POTTER_GOBLET_OF_FIRE1.vob -croptop 80 -cropbottom 80 -t 00:01:00 -ss 00:00:00 -an -sameq -f flv -qscale $x video$x.flv; done

FFmpeg version 0.5-svn17737+3:0.svn20090303-1ubuntu4, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --extra-version=svn17737+3:0.svn20090303-1ubuntu4 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --disable-stripping --disable-vhook --enable-libdc1394 --enable-shared --disable-static
  libavutil 49.15. 0 / 49.15. 0
  libavcodec 52.20. 0 / 52.20. 0
  libavformat 52.31. 0 / 52.31. 0
  libavdevice 52. 1. 0 / 52. 1. 0
  libavfilter 0. 4. 0 / 0. 4. 0
  libswscale 0. 7. 1 / 0. 7. 1
  libpostproc 51. 2. 0 / 51. 2. 0
  built on Mar 23 2009 07:13:25, gcc: 4.3.3

Seems stream 0 codec frame rate differs from container frame rate: 50.00 (50/1) -> 25.00 (25/1)
Input #0, mpeg, from 'HARRY_POTTER_GOBLET_OF_FIRE1.vob':
  Duration: 01:15:42.86, start: 0.052000, bitrate: 12699 kb/s
    Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 DAR 16:9], 7500 kb/s, 25 tbr, 90k tbn, 50 tbc
    Stream #0.1[0x80]: Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s
    Stream #0.2[0x81]: Audio: ac3, 0 channels, s16
Output #0, flv, to 'video1.flv':
    Stream #0.0: Video: flv, yuv420p, 720x416 [PAR 227:221 DAR 10215:5746], q=2-31, 200 kb/s, 90k tbn, 25 tbc
Stream mapping:
  Stream #0.0 -> #0.0
Press [q] to stop encoding
frame= 1501 fps=103 q=0.0 Lsize= 12920kB time=60.04 bitrate=1762.8kbits/s
video:12896kB audio:0kB global headers:0kB muxing overhead 0.183273%
FFmpeg version 0.5-svn17737+3:0.svn20090303-1ubuntu4, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --extra-version=svn17737+3:0.svn20090303-1ubuntu4 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --disable-stripping --disable-vhook --enable-libdc1394 --enable-shared --disable-static
  libavutil 49.15. 0 / 49.15. 0
  libavcodec 52.20. 0 / 52.20. 0
  libavformat 52.31. 0 / 52.31. 0
  libavdevice 52. 1. 0 / 52. 1. 0
  libavfilter 0. 4. 0 / 0. 4. 0
  libswscale 0. 7. 1 / 0. 7. 1
  libpostproc 51. 2. 0 / 51. 2. 0
  built on Mar 23 2009 07:13:25, gcc: 4.3.3

Seems stream 0 codec frame rate differs from container frame rate: 50.00 (50/1) -> 25.00 (25/1)
Input #0, mpeg, from 'HARRY_POTTER_GOBLET_OF_FIRE1.vob':
  Duration: 01:15:42.86, start: 0.052000, bitrate: 12699 kb/s
    Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 DAR 16:9], 7500 kb/s, 25 tbr, 90k tbn, 50 tbc
    Stream #0.1[0x80]: Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s
    Stream #0.2[0x81]: Audio: ac3, 0 channels, s16
Output #0, flv, to 'video2.flv':
    Stream #0.0: Video: flv, yuv420p, 720x416 [PAR 227:221 DAR 10215:5746], q=2-31, 200 kb/s, 90k tbn, 25 tbc
Stream mapping:
  Stream #0.0 -> #0.0
Press [q] to stop encoding
frame= 1501 fps= 98 q=0.0 Lsize= 12920kB time=60.04 bitrate=1762.8kbits/s
video:12896kB audio:0kB global headers:0kB muxing overhead 0.183273%
FFmpeg version 0.5-svn17737+3:0.svn20090303-1ubuntu4, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --extra-version=svn17737+3:0.svn20090303-1ubuntu4 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --disable-stripping --disable-vhook --enable-libdc1394 --enable-shared --disable-static
  libavutil 49.15. 0 / 49.15. 0
  libavcodec 52.20. 0 / 52.20. 0
  libavformat 52.31. 0 / 52.31. 0
  libavdevice 52. 1. 0 / 52. 1. 0
  libavfilter 0. 4. 0 / 0. 4. 0
  libswscale 0. 7. 1 / 0. 7. 1
  libpostproc 51. 2. 0 / 51. 2. 0
  built on Mar 23 2009 07:13:25, gcc: 4.3.3

Seems stream 0 codec frame rate differs from container frame rate: 50.00 (50/1) -> 25.00 (25/1)
Input #0, mpeg, from 'HARRY_POTTER_GOBLET_OF_FIRE1.vob':
  Duration: 01:15:42.86, start: 0.052000, bitrate: 12699 kb/s
    Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 DAR 16:9], 7500 kb/s, 25 tbr, 90k tbn, 50 tbc
    Stream #0.1[0x80]: Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s
    Stream #0.2[0x81]: Audio: ac3, 0 channels, s16
Output #0, flv, to 'video3.flv':
    Stream #0.0: Video: flv, yuv420p, 720x416 [PAR 227:221 DAR 10215:5746], q=2-31, 200 kb/s, 90k tbn, 25 tbc
Stream mapping:
  Stream #0.0 -> #0.0
Press [q] to stop encoding
frame= 1501 fps= 99 q=0.0 Lsize= 12920kB time=60.04 bitrate=1762.8kbits/s
video:12896kB audio:0kB global headers:0kB muxing overhead 0.183273%
FFmpeg version 0.5-svn17737+3:0.svn20090303-1ubuntu4, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --extra-version=svn17737+3:0.svn20090303-1ubuntu4 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --disable-stripping --disable-vhook --enable-libdc1394 --enable-shared --disable-static
  libavutil 49.15. 0 / 49.15. 0
  libavcodec 52.20. 0 / 52.20. 0
  libavformat 52.31. 0 / 52.31. 0
  libavdevice 52. 1. 0 / 52. 1. 0
  libavfilter 0. 4. 0 / 0. 4. 0
  libswscale 0. 7. 1 / 0. 7. 1
  libpostproc 51. 2. 0 / 51. 2. 0
  built on Mar 23 2009 07:13:25, gcc: 4.3.3

Seems stream 0 codec frame rate differs from container frame rate: 50.00 (50/1) -> 25.00 (25/1)
Input #0, mpeg, from 'HARRY_POTTER_GOBLET_OF_FIRE1.vob':
  Duration: 01:15:42.86, start: 0.052000, bitrate: 12699 kb/s
    Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 DAR 16:9], 7500 kb/s, 25 tbr, 90k tbn, 50 tbc
    Stream #0.1[0x80]: Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s
    Stream #0.2[0x81]: Audio: ac3, 0 channels, s16
Output #0, flv, to 'video4.flv':
    Stream #0.0: Video: flv, yuv420p, 720x416 [PAR 227:221 DAR 10215:5746], q=2-31, 200 kb/s, 90k tbn, 25 tbc
Stream mapping:
  Stream #0.0 -> #0.0
Press [q] to stop encoding
frame= 1501 fps=103 q=0.0 Lsize= 12920kB time=60.04 bitrate=1762.8kbits/s
video:12896kB audio:0kB global headers:0kB muxing overhead 0.183273%
FFmpeg version 0.5-svn17737+3:0.svn20090303-1ubuntu4, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --extra-version=svn17737+3:0.svn20090303-1ubuntu4 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --disable-stripping --disable-vhook --enable-libdc1394 --enable-shared --disable-static
  libavutil 49.15. 0 / 49.15. 0
  libavcodec 52.20. 0 / 52.20. 0
  libavformat 52.31. 0 / 52.31. 0
  libavdevice 52. 1. 0 / 52. 1. 0
  libavfilter 0. 4. 0 / 0. 4. 0
  libswscale 0. 7. 1 / 0. 7. 1
  libpostproc 51. 2. 0 / 51. 2. 0
  built on Mar 23 2009 07:13:25, gcc: 4.3.3

Seems stream 0 codec frame rate differs from container frame rate: 50.00 (50/1) -> 25.00 (25/1)
Input #0, mpeg, from 'HARRY_POTTER_GOBLET_OF_FIRE1.vob':
  Duration: 01:15:42.86, start: 0.052000, bitrate: 12699 kb/s
    Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 DAR 16:9], 7500 kb/s, 25 tbr, 90k tbn, 50 tbc
    Stream #0.1[0x80]: Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s
    Stream #0.2[0x81]: Audio: ac3, 0 channels, s16
Output #0, flv, to 'video5.flv':
    Stream #0.0: Video: flv, yuv420p, 720x416 [PAR 227:221 DAR 10215:5746], q=2-31, 200 kb/s, 90k tbn, 25 tbc
Stream mapping:
  Stream #0.0 -> #0.0
Press [q] to stop encoding
frame= 1501 fps=104 q=0.0 Lsize= 12920kB time=60.04 bitrate=1762.8kbits/s
video:12896kB audio:0kB global headers:0kB muxing overhead 0.183273%

0 nido@toad:~/ ls -la video[12345].flv
-rw-r--r-- 1 nido nido 13230180 2009-04-02 14:00 video1.flv
-rw-r--r-- 1 nido nido 13230180 2009-04-02 14:00 video2.flv
-rw-r--r-- 1 nido nido 13230180 2009-04-02 14:00 video3.flv
-rw-r--r-- 1 nido nido 13230180 2009-04-02 14:00 video4.flv
-rw-r--r-- 1 nido nido 13230180 2009-04-02 14:01 video5.flv

[Reinhard Tartler (siretart)]

Nido Media <email address hidden> writes:

> using ffmpeg comming with ubuntu jaunty (which is FFmpeg version
> 0.5=-svn17737+3:0.svn20090303-1ubuntu4); usage of the -qscale rather then -b
> doesn't change the end result file size. In fact; coding a flv video five times
> with qscale going from 1 to 5 has no effect; using 25 doesn't quite make the
> video any smaller or less nice to watch.

could you please check if that also happens with the latest version from
trunk?

--
Gruesse/greetings,
Reinhard Tartler, KeyID 945348A4

[Nido Media (nido)]

it works with svn for flv video; theora video, however; still doesn't care about the quantizer:

for x in 1 5 25; do /home/nido/bin/programs/ffmpeg/bin/ffmpeg -y -vframes 250 -i in.flv -qscale $x -s vga out$x.flv; done
for x in 1 5 25; do /home/nido/bin/programs/ffmpeg/bin/ffmpeg -y -vframes 250 -i in.flv -qscale $x -s vga out$x.flv; done
ls -lh

-rw-r--r-- 1 nido nido 798K 2009-04-06 21:17 out1.avi
-rw-r--r-- 1 nido nido 5.2M 2009-04-06 21:18 out1.flv
-rw-r--r-- 1 nido nido 798K 2009-04-06 21:17 out25.avi
-rw-r--r-- 1 nido nido 1.1M 2009-04-06 21:18 out25.flv
-rw-r--r-- 1 nido nido 798K 2009-04-06 21:17 out5.avi
-rw-r--r-- 1 nido nido 2.5M 2009-04-06 21:18 out5.flv

[Nido Media (nido)]

you can find it in upstream here: https://roundup.ffmpeg.org/roundup/ffmpeg/issue949?@ok_message=msg%204825%20created%3Cbr%3Eissue%20949%20status%2C%20messages%2C%20substatus%20edited%20ok&@template=item

[Reinhard Tartler (siretart)]

okay, this means this needs forwarding upstream.

--
Gruesse/greetings,
Reinhard Tartler, KeyID 945348A4

[Reinhard Tartler (siretart)]

thanks for forwarding it. This is a better url: https://roundup.ffmpeg.org/roundup/ffmpeg/issue949

as soon as it has been fixed in HEAD we can consider backporting it to the 0.5 release.

[Nido Media (nido)]

May I know what is incomplete about this bug?

[Paul Gevers (paul-climbing)]

You should look (and ask) upstream. That is where the incomplete message
come from. Except that upstream says closed/implemented and NOT
incomplete. This is probably a bug in Launchpad.

Paul

Nido Media wrote:
> May I know what is incomplete about this bug?
>

[Reinhard Tartler (siretart)]

this is the patch from upstream.

can someone test it? it looks good to me, so I'll add it to the package on the next upload

[Nido Media (nido)]

356322.patch applies cleanly on ffmpeg-debian-0.svn20090303 (which i got from `apt-get source ffmpeg`). Testing compliling and running now

[Nido Media (nido)]

seems to work like a charm. What I did to accomplish this:

sudo su -
apt-get source ffmpeg
apt-get build-dep ffmpeg
cd ffmpeg-debian-0.svn20090303
dpkg-buildpackage -rfakeroot -uc -b
cd ..
dpkg -i *.deb

exit

for x in 1 5 25; do ffmpeg -y -vframes 250 -i in.avi -qscale $x -s vga out$x.ogg; done
ls -lah out*.ogg

output of the last command:
-rw-r--r-- 1 nido nido 865K Oct 2 15:23 out1.ogg
-rw-r--r-- 1 nido nido 2.3M Oct 2 15:23 out25.ogg
-rw-r--r-- 1 nido nido 1.2M Oct 2 15:23 out5.ogg

Seems like it's working.

[Launchpad Janitor (janitor)]

This bug was fixed in the package ffmpeg - 4:0.5+svn20090706-2ubuntu2

---------------
ffmpeg (4:0.5+svn20090706-2ubuntu2) karmic; urgency=low

  [ Reinhard Tartler ]
  * Make arguments of av_set_pts_info() unsigned.
  * update debian/changelog
  * use patch for issue1245 from git.ffmpeg.org
  * Support constant-quant encoding for libtheora, LP: #356322
  * increase swscale compile time width (VOF/VOFW), LP: #443264

  [ Loïc Minier ]
  * Update config for karmic's armel toolchain.
  * Enable neon flavour; LP: #383240.
  * Update NEON confflags to assume v7 and VFP.
  * Add backported NEON patches from ffmpeg trunk; see debian/patches/neon/.
  * Pass proper --cpu and --extra-flags on armel.
  * Pass -fPIC -DPIC to neon pass.

 -- Loic Minier <email address hidden> Tue, 13 Oct 2009 23:56:04 +0200

[Paul Gevers (paul-climbing)]

Closing this old bug manually, as according to my comment #7 the bug upstream was closed and the upstream link does not work anymore.

[alvgarci (alvaro-garcia-gonzalo)]

Hi:

Same issue in FFMPEG on MacOS 10.7.3.

Any solution for that?

Thanks

[Paul Gevers (paul-climbing)]

@alvgarci,

The bug is fixed in both Ubuntu and in upstream ffmpeg/libav. So you will have to ask you distribution for the fix. This is definitely the wrong place, although there might be useful information for the developers of your distribution.