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bigfatass
11-26-2002, 08:36 AM
After about 2 weeks I now am at the stage where I can pull M2V and M2A files from my tivo fairly reliably. I have used TivoWEB to alter the bitrates and resolution for medium to 480x480 (2) and 2150000 vbr 2500000 max. My only problem comes in muxing (??) the two files together. I've seen a few articles recommending various programs but am currently trying BBMpeg (avi2mpg2). This seemed to work mostly and also only takes about 3-5 mins to generate a finished .mpg plus the audio-sync is easy enough to get right.

So here is my problem / question:


video DTS (1047100.00ms) underflow at pack 160862 by 25313.33ms
video PTS (1047140.00ms) underflow at pack 160876 by 25366.67ms

I get literally thousands of these messages while BBMpeg is working. At the bottom it says:


25922 video underflows (SCR >= PTS or DTS)
NOTE: The resulting file may not play back correctly. Try reducing the video bitrate or increasing the video and audio startup delays.
Finished multiplexing temp.mpg

So assuming the error is being helpful, which of these suggestions should i try ? And what delays / bitrates should I try next to solve this.

I found the resultant mpg played and synced pretty well until about 10 mins in when the video started jumping frames and it became unwatchable.

Cheers
--
Pete

UK Thompson Tivo v2.5.5-01-1-023
Turbonet + 60Gig upgrade

jdiner
11-26-2002, 01:54 PM
There are bit rate settings, call them profiles, in bbmpeg. These specify what to expect and what to do with that expectation.

If you pick VCD the bit rates are solidly fixed by the specs. If you pick SVCD the bit rates have a bit more flexibility but you still need to be within a certain range. DVD is much higher but still limited.

The bit rate is simply the amount of bits for a full second of audio, video, and any and all MPEG packaging and there is a fair amount of this.

So you picked "2150000 vbr 2500000 " but this is to high for VCD and I believe still to high for SVCD. but works for DVD.

So you can have 1,150,000 IIRC for VCD. And up to 2 times that for SVCD in general terms. What you listed above is too high.

So how you get off. every "block" in the mux'ed output uses so many bytes. Given the profile you chose to do this with you get an upper limit. 1000 blocks in a second. But given your data rate and resulting size you need 1100 blocks to actually hold it. This is how you get off.

So either lower your data rate or raise the profile levels in bbmpeg so that it has enough "room" for the data to be multiplexed.

--jdiner

bigfatass
12-04-2002, 01:08 PM
Thanks for that.

Is there a site I should keep checking for new versions of tytool (with mux support :D) or will it be posted on this forum first ?

wallmartian
12-04-2002, 02:42 PM
bfa,

This is the place to be for any new releases from jdiner, he is the author of TyTool5. I'm sure he'll post any new releases here as soon as he has them ready :D

wm