[Ffmpeg-devel] Hmmm interesting...

Erik Slagter erik
Fri Mar 24 20:14:48 CET 2006

With x264/ffmpeg/mplayer from today (and at least from last week) I have
an interesting phenomenon, but I am not sure which one is guilty ;-)

Option #1: ffmpeg makes raw h264 and aac streams, multiplexed by gpac:

ffmpeg -i "$vob" -y -nr 800 -bf 16 -t 15 -threads 2 \
-trellis 1 -qmin 10 -qmax 51 -b 1500 -deinterlace \
-aspect 4:3 -minrate 0 -maxrate 2000 -bufsize 1000 \
-coder 1 -loop 1 -cmp 256 -me hex -me_range 16 \
-subq 5 -g 250 -sc_threshold 40 -rc_eq 'blurCplx^(1-qComp)' \
-partitions parti4x4+partp8x8+partb8x8 \
-vcodec h264 -an -f h264 "$video"

time ffmpeg -i "$vob" -y -vn -acodec aac -ab 128 -f aac  "$audio"

MP4Box -add $video -add $audio -new $mp4

Resulting video plays fine in ffplay, mplayer and vlc.

Option #2: ffmpeg makes h264 and aac in mp4:

time ffmpeg -i "$vob" -y -nr 800 -bf 16 -t 15 \
-threads 2 -trellis 1 -qmin 18 -qmax 51 -b 1500  \
-deinterlace -aspect 4:3 -minrate 0 -maxrate 2000 \
-bufsize 1000 -coder 1 -loop 1 -cmp 256 \
-me hex -me_range 16 -subq 5 -g 250 -sc_threshold 40 \
-rc_eq 'blurCplx^(1-qComp)' \
-partitions parti4x4+partp8x8+partb8x8 \
-vcodec h264 -acodec aac -ab 128 -f mp4 "$mp4"

FWIW, the video and audio encoding options are actually the same as in
option #1. Also the video and audio encoding option do not seem to
matter for the issue I am having.

The issue: in mplayer this shows a very light picture, like the
brightness on a CRT has been turned up all the way. Seeking is
troublesome, although the brightness disappears after some seeking, even
at the beginning.

But: ffplay and vlc play the stream more or less ok, although both choke
when seeking in the stream.

I remuxed the stream using gpac and the problem remains!

Looks to me like a bad interaction between either aac and mp4, or h264
and mp4? As both have had some changes lately I am not sure where to
search. I don't remember having had this phenomenon two weeks ago, so it
looks like a regression.

Input and output streams can be found here: http://erik.slagter.name/pub
- in.vob source, 86 Mb, only start is relevant
- out.mp4 result, 15 secs, 2 Mb

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