[Ffmpeg-devel] Bad interation of rc_strategy=1 and qprd

[Nico Sabbi]

Loren Merritt wrote:

> On Sat, 4 Feb 2006, Nico Sabbi wrote:
>
>> Michael Niedermayer wrote:
>>
>>>
>>> well, you at least have to post 1st pass, 2nd pass stats of lavc, 
>>> lavc+xvid_rc
>>> and xvid ...
>>
>>
>> I'm not comparing the two codecs (I prefer lavc much more than xvid):
>> I'm only encoding to lavc (mpeg2) with and without vrc_strategy=1 to 
>> see if there is any improvement.
>> I'll post the psnr figures when I've collected them
>
>
> But you should compare lavc+xvid_rc against xvid+xvid_rc, otherwise 
> you won't know if you've accurately implemented xvid_rc.
>
> First guess for why qprd borks: did you not set lambda appropriately? 
> xvid's rc deals only with quantizers.
>
> --Loren Merritt
>

here are the results; if you need more tests let me know.
Visually mpeg4 looks much better to my eyes, both with vrc_strategy=0 
and with vrc_strategy=1.
PSNR figures for vcodec=xvid are not available.
The common part of the command line is:
mencoder -nosound -vf field -force-avi-aspect 4/3 -ovc lavc -endpos 600 
test.ts

LAVC mpeg4:

vpass=1:keyint=25:vcodec=mpeg4:mbd=2:vbitrate=1000:vmax_b_frames=0:psnr 
-endpos 600 test.ts
Video stream: 1003.221 kbit/s  (125402 B/s)  size: 75246605 bytes  
600.040 secs  15002 frames
PSNR: Y:35.43, Cb:41.11, Cr:42.19, All:36.70

vpass=2:keyint=25:vcodec=mpeg4:mbd=2:vbitrate=1000:vmax_b_frames=0:psnr 
-endpos 600 test.ts
Video stream: 1000.593 kbit/s  (125074 B/s)  size: 75049474 bytes  
600.040 secs  15002 frames
PSNR: Y:35.74, Cb:41.35, Cr:42.39, All:37.00



vpass=1:vrc_strategy=1:keyint=25:vcodec=mpeg4:mbd=2:vbitrate=1000:vmax_b_frames=0:psnr 
-endpos 600 test.ts
Video stream: 1003.221 kbit/s  (125402 B/s)  size: 75246605 bytes  
600.040 secs  15002 frames
PSNR: Y:35.43, Cb:41.11, Cr:42.19, All:36.70

vpass=2:vrc_strategy=1:keyint=25:vcodec=mpeg4:mbd=2:vbitrate=1000:vmax_b_frames=0:psnr 
-endpos 600 test.ts
Video stream:  999.645 kbit/s  (124955 B/s)  size: 74978386 bytes  
600.040 secs  15002 frames
PSNR: Y:35.33, Cb:41.06, Cr:42.17, All:36.60



vpass=1:vrc_strategy=1:keyint=25:vcodec=mpeg4:mbd=2:vbitrate=1000:vmax_b_frames=0:qprd:psnr 
-endpos 600 test.ts
Video stream: 1003.037 kbit/s  (125379 B/s)  size: 75232780 bytes  
600.040 secs  15002 frames
PSNR: Y:35.51, Cb:41.03, Cr:42.11, All:36.76

vpass=2:vrc_strategy=1:keyint=25:vcodec=mpeg4:mbd=2:vbitrate=1000:vmax_b_frames=0:qprd:psnr 
-endpos 600 test.ts
Video stream: 6276.007 kbit/s  (784500 B/s)  size: 470731933 bytes  
600.040 secs  15002 frames
PSNR: Y:44.06, Cb:47.02, Cr:47.74, All:44.91



vpass=1:vrc_strategy=1:keyint=25:vcodec=mpeg4:mbd=2:vbitrate=1000:vmax_b_frames=0:qprd:psnr:vqmin=2:vqmax=31
Video stream: 1003.037 kbit/s  (125379 B/s)  size: 75232780 bytes  
600.040 secs  15002 frames
PSNR: Y:35.51, Cb:41.03, Cr:42.11, All:36.76

vpass=2:vrc_strategy=1:keyint=25:vcodec=mpeg4:mbd=2:vbitrate=1000:vmax_b_frames=0:qprd:psnr:vqmin=2:vqmax=31
Video stream: 6276.007 kbit/s  (784500 B/s)  size: 470731933 bytes  
600.040 secs  15002 frames
PSNR: Y:44.06, Cb:47.02, Cr:47.74, All:44.91


XVID:

vpass=1:vrc_strategy=0:keyint=25:vcodec=xvid:mbd=2:vbitrate=1000:vmax_b_frames=0:psnr
Video stream: 5006.613 kbit/s  (625826 B/s)  size: 375521025 bytes  
600.040 secs  15002 frames
PSNR: Y:nan, Cb:nan, Cr:nan, All:nan

vpass=2:vrc_strategy=0:keyint=25:vcodec=xvid:mbd=2:vbitrate=1000:vmax_b_frames=0:psnr
Video stream:  996.835 kbit/s  (124604 B/s)  size: 74767579 bytes  
600.040 secs  15002 frames
PSNR: Y:nan, Cb:nan, Cr:nan, All:nan



vpass=1:vrc_strategy=0:keyint=25:vcodec=xvid:mbd=2:vbitrate=1000:vmax_b_frames=0:qprd:psnr
Video stream: 5006.613 kbit/s  (625826 B/s)  size: 375521025 bytes  
600.040 secs  15002 frames
PSNR: Y:nan, Cb:nan, Cr:nan, All:nan

vpass=2:vrc_strategy=0:keyint=25:vcodec=xvid:mbd=2:vbitrate=1000:vmax_b_frames=0:qprd:psnr
Video stream:  996.835 kbit/s  (124604 B/s)  size: 74767579 bytes  
600.040 secs  15002 frames
PSNR: Y:nan, Cb:nan, Cr:nan, All:nan


vpass=1:vrc_strategy=1:keyint=25:vcodec=xvid:mbd=2:vbitrate=1000:vmax_b_frames=0:psnr
Video stream: 5006.613 kbit/s  (625826 B/s)  size: 375521025 bytes  
600.040 secs  15002 frames
PSNR: Y:nan, Cb:nan, Cr:nan, All:nan

vpass=2:vrc_strategy=1:keyint=25:vcodec=xvid:mbd=2:vbitrate=1000:vmax_b_frames=0:psnr
Video stream:  996.835 kbit/s  (124604 B/s)  size: 74767579 bytes  
600.040 secs  15002 frames
PSNR: Y:nan, Cb:nan, Cr:nan, All:nan


vpass=1:vrc_strategy=1:keyint=25:vcodec=xvid:mbd=2:vbitrate=1000:vmax_b_frames=0:qprd:psnr
Video stream: 5006.613 kbit/s  (625826 B/s)  size: 375521025 bytes  
600.040 secs  15002 frames
PSNR: Y:nan, Cb:nan, Cr:nan, All:nan

vpass=2:vrc_strategy=1:keyint=25:vcodec=xvid:mbd=2:vbitrate=1000:vmax_b_frames=0:qprd:psnr
Video stream:  996.835 kbit/s  (124604 B/s)  size: 74767579 bytes  
600.040 secs  15002 frames
PSNR: Y:nan, Cb:nan, Cr:nan, All:nan


vpass=1:vrc_strategy=1:keyint=25:vcodec=xvid:mbd=2:vbitrate=1000:vmax_b_frames=0:qprd:psnr:vqmin=2:vqmax=31
Video stream: 5006.613 kbit/s  (625826 B/s)  size: 375521025 bytes  
600.040 secs  15002 frames
PSNR: Y:nan, Cb:nan, Cr:nan, All:nan

vpass=2:vrc_strategy=1:keyint=25:vcodec=xvid:mbd=2:vbitrate=1000:vmax_b_frames=0:qprd:psnr:vqmin=2:vqmax=31
Video stream:  996.835 kbit/s  (124604 B/s)  size: 74767579 bytes  
600.040 secs  15002 frames
PSNR: Y:nan, Cb:nan, Cr:nan, All:nan



    Nico