Re: [transcode-users] rc buffer underflow with ffmpeg

[Erik Slagter <erik@xxxxxxxxxxxxx>]

On Tue, 2005-03-01 at 18:32 -0700, Chris McBride wrote:
> I was trying to use ffmpeg (instead of mpeg2enc) to encode some clips of 
> stuff I captured & have been getting rc buffer underflow message(s).

This is no error. It is normal at the beginning of encoding. Ignore it.
I've already requested to remove it from ffmpeg.

> When encoding the same clip with mpeg2enc I do not get any errors but it is 
> slowwwww......

Yep...

> transcode --export_asr 2 -w 7000 -i movie.avi -y ffmpeg,mp2enc -F mpeg2video 
> -M 2 --print_status 20 -F '8,-B 348 -d -z t -n n' --encode_fields t 
> --a52_drc_off -x mplayer="-contrast -10 -vf hqdn3d" -x mplayer -K -a 0 -H 10 
> --export_prof dvd-ntsc -j -12,-4,-12,-4 --pre_clip 12,4,12,4 -E 48000,16,2 
> -b 224 -m audio-ffmpeg -o video-ffmpeg -c 5000-7000

See my example command line. If you want more more speed ;-) you can
also use
ffmpeg to do the mp2 encoding & resampling, but you'll lose a bit
quality.


> I have tried some different options in ffmpeg.cfg - here is my basic file:
> 
> [mpeg2video]
> vhq = 1

This one is obsolete.

Use mbd = 0 | 1 | 2

Where 0 is fastest and 2 is max quality. It doesn't make too much
difference though, so check.

> vqsquish = 0
> vqcomp = 0.7
> vqblur = 0.3
> vrc_minrate=0
> vrc_maxrate=9800
> # vrc_buf_size=1792 # suggestion online
> vrc_buf_size=1835 # DVD setting in man page

Remove them all. They are either marginally functional
or already set by the dvd export profile (you should really
use that!).