WMV9 bidirectional frames performance

noam_korem · 26th October 2005, 16:27

I've been playing around with several WMV encoders (including one from MS), and it seems like this standard exhibits low performance concerning B-frames.

While MPEG4's use of B frames usually reduce bitstream size by 10-20% (in relation to P-only streams), the WMV standard rarely shows any reduction at all (!).

The encoders I checked supported 1-7 consecutive B frames, 4MV, AC prediction, and all the knacks and gadgets available in the standard. It simply seems like WMV B frames are not cheap enough, while distancing the P-vops from one another demands a large amount of bits...

Can anyone comment on this? I'd like to know if this phenomenon is familiar, or am I doing something wrong?

NK.

26th October 2005, 16:27	#1 \| Link
noam_korem Registered User Join Date: Oct 2005 Location: Israel Posts: 9	WMV9 bidirectional frames performance I've been playing around with several WMV encoders (including one from MS), and it seems like this standard exhibits low performance concerning B-frames. While MPEG4's use of B frames usually reduce bitstream size by 10-20% (in relation to P-only streams), the WMV standard rarely shows any reduction at all (!). The encoders I checked supported 1-7 consecutive B frames, 4MV, AC prediction, and all the knacks and gadgets available in the standard. It simply seems like WMV B frames are not cheap enough, while distancing the P-vops from one another demands a large amount of bits... Can anyone comment on this? I'd like to know if this phenomenon is familiar, or am I doing something wrong? NK.

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