TMPGEnc: Question about avgerage and maximum VBR.

[ChachiFace]

I'm encoding .avi to .m2v + .wav (PCM) using TMPGEnc Plus. I want to keep my quality on the high end but also want to salvage disc space since I'm using PCM audio (sharper) so I'm using VBR rather than CBR. I was previously using a combo of 6000 avg/8000 max/0 min. but found that my discs would not fast forward in some players. I suspect that this is due to the max bitrate + PCM audio bitrate "clipping". So I want to try encoding using a bitrate combo of 6000 avg/6000 max/0 min. This way 6000 would be the max but the avgerage also and would have room to drop the bitrate if needed which would save some disc space. So my question is, is this breaking some sort of rule by encoding using the same avg/max values? I'm trying it now but not done encoding. I just want to be sure that I'm not going to worsen my compatibility.

Thanks,

ChachiFace

[SaSi]

Setting the average bitrate equal to the maximum makes this a trivial case of CBR encoding. So if you are encoding in two passes, the second one is wasted.

Agreeably, 8000kbps max with LPCM is rather high. 7500kbps though would not really be. So, keep the 6000 as an average and clip out the max to 7500.

By the way, you mentioned that LPCM is sharper. What exactly do you mean?

[ZippyP.]

This way 6000 would be the max but the avgerage also and would have room to drop the bitrate if needed which would save some disc space.

The bitrate will not drop below 6000 if the average and the maximum are 6000. In order to go below 6000 in some place it needs to go above 6000 in another in order to maintain the 6000 average. You might as well do a 6000 CBR encode in half the time. Either drop the average below 6000 or raise the maximum like Sasi said.

[ChachiFace]

Hmmm... thanks for the responses. Glad I asked. I tried using a max of 7k and the avg at 6k but I'm still having trouble with the fast forward/rewind (search) function halting with my discs' in some DVD players. It may or may not be induced by a max bitrate clip, I did notice however that when ever the search function cuts on the DVD player that the bitrate on the display peeks out between 9-12kbps.

By "sharper" I just mean that with my experience, PCM has a "sharper" tone vs ac3 or anything else.

[ZippyP.]

It may or may not be induced by a max bitrate clip, I did notice however that when ever the search function cuts on the DVD player that the bitrate on the display peeks out between 9-12kbps.

I do know that TMPGEnc will sometimes exceed the maximum setting and give bitrate spikes. It sometimes chokes my DVD player on SVCD's. Why it does that I do not know. Try a CBR encode and see if the problem goes away.

[ChachiFace]

ZippyP. -

Thanks for your reply!

I noticed the spikes too but wasn't sure if it's TMPGEnc or what. I've got two encodes going right now: 1. CBR of 6000kbps using TMPGEnc and 2. VBR of 6000kbps avg/7000kbps max using Mainconcept. I'll post the results once I know them.

ChachiHead