[andiandi]

Hi.

I made some encoding tests with a full movie in 720p 1800Kbps which have few grain and many high motion scenes, to look at final ratefactor and frames quantizer :



- B-frames + mbtree (rc-lookahead:50) :

final ratefactor: 21.75
frame I:1543 Avg QP:19.34 size: 72976
frame P:35636 Avg QP:22.32 size: 19431
frame B:111983 Avg QP:24.61 size: 5236


- No B-frames + mbtree (rc-lookahead:50) :

final ratefactor: 22.82
frame I:3370 Avg QP:22.10 size: 34683
frame P:145792 Avg QP:24.11 size: 8770

- No-mbtree + pb-ratio 1.0 :

final ratefactor: 23.48
frame I:1521 Avg QP:21.07 size: 54209
frame P:36751 Avg QP:23.47 size: 15013
frame B:110890 Avg QP:23.37 size: 6827

- No-mbtree + pb-ratio 1.1 :

final ratefactor: 22.90
frame I:1521 Avg QP:21.09 size: 54120
frame P:36751 Avg QP:22.94 size: 16398
frame B:110890 Avg QP:23.54 size: 6377



As we can see, based on the final ractefactor (if it's relevant enough), it confirms that No B-frames + mbtree gives a better compression than pb-ratio without mbtree.

But frames quantizer shows that for No b-frames + mbtree, p-frames have a worse quantizer than both p-frames and b-frames with pb-ratio + no-mbtree.

I don't know how to feel about it since both (no b-frame + mbtree and pbratio + no-mbtree) seems to have their advantages.