On Mon, 3 Nov 2003, Andrew Stevens wrote:
> Well... its got a little way to go before its professional quality...
It's getting closer every week/month though ;)
> So, to compare like with like you have to compare default mpeg2enc and MPEG-4
> encoder encoding full CCITT 720x<Y> pictures with interlaced motion modes
> active and a BBP picture structure *and* identical pre-encoder processing.
Indeed! When I see folks boast about 'real time' encoding
(usually with ffmpeg's MPEG4/DivX) they're using SIF (352x240/352x288)
and not full 720x<Y> sized data - they're also not using B frames
which as Andrew mentions are very cpu intensive.
The only time I've seen encoding rates at or below 3fps is on my older
Pentium3 systems.
> - Go to P frames only (this may sometimes even improve compression!).
If you do that (and it has almost always improved the compression for
me - sometimes quite substantially) then you may encounter playback
difficulties with Ogle - seems they don't handle the dual prime
motion estimation :( Other players (including settop boxes) have
no problem though.
With noisier material the savings from turning off B frames are
often on the order of 10 or 15% on filesize.
> For example, on my 1700Mhz Athlon/XP, 243 Frames of NTSC (720x480) Movie
> Note: this is just the encoder. It is common for the MJPEG decoding and
> denoising/scaling etc etc to use pretty much the same CPU resources.
I've noticed that yuvdenoise tends to be limited to 5 or 6 frames/sec
so adding that to the mix introduces a bottleneck - at least for me.
> -f 8 -E -10 -q 6 -K tmpgenc
> user 0m34.014s = 7.1 Frame/sec
> -f 8 -E -10 -q 6 -R 0 -I 0 -K tmpgenc
> user 0m14.580s = 16.6 Frame/sec
Ah, quite similar settings to what I've settled on ;)
I've too have found that "-q 6 -E -10 -K tmpgenc" produces very
good quality output.
Hmmm, without the -I 0 I only get about 15 Frame/sec on my Athlon
2800. Does -I 0 make that big of a difference?
Cheers,
Steven Schultz
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