Bitrate issue with seamless multi-angle

[galinette69]

Hi all,

I want to author a DVD with a 2 hours movie, where 3 chapters over the 18 have a second angle (basically showing a slideshow that has been converted to movie, and edited to be synchronized to the main video). This should be very close to DVD movies where some text parts (credits, ...) are multi-language, such as Shrek or Star-wars.

In order to switch to these chapters seamlessly, I have followed a scenarist guide found on doom9. I create tracks of every single-angle or multi-angle part. I then add these tracks to the a common PGC, so that all cells except the first are flagged "SM" (seamless)

However, I cannot manage to export the DVD, scenarist fails during muxing the first multiangle part, with a "bitrate too high" error.

I encode with CCE, and I did at least 10 trials reencoding everything to manage a succesful mux in scenarist, but without success. I have a single AC3 448kbps track.
Here is what I tried incrementally in CCE:

- Check the "DVD multiangle" option
- Lower the max bitrate of the multiangle parts to 7000
- Uncheck "for DVD" as is it reported to enforce the max bitrate to 9800
- Lower the max bitrate of the single angle parts to 7000
- Check the "DVD multiangle" option in single-angle parts
- Uncheck "for DVD" on all parts
- Use the same bitrate for all parts
- Use 3500kbps max bitrate for all parts
- Finally, I used these settings:

bitrate : min:0 avg:3000 max:3500
for DVD : unchecked
multiangle DVD : checked
VBR passes : 4

And I always have the same error message... Here is the detail of it:

Warning Total bitrate too HIGH. Video buffer underflow (DTS=146664 SCR=150272) (around 00:00:01;16).
Info picture_type: IPBPBBPBBPBB
Info picture_size: 175744 9084 1072 5628 1016 1000 3956 956 900 3112 860 796
Info gop bitrate: 3402066
Error dvd_mux : DoMux Multiplexing Error
Error Terminated Multiplexing (dvd2-02a_1_t.vob.1).
Error Total bitrate is too HIGH. Please reduce the stream bitrate or the number of stream.


3402066 should be the bitrate in cause??? It's perfectly under the max value specified (3500k).

Thanks for advice...

[bbjay]

First off, always use CBR when doing multiangle. 2nd get a bitrate viewer to check your stream for spikes (http://www.tecoltd.com/bitratev.htm). If your spikes are too high then it will not mux. Yes even in CBR there will be fluctuation in the bit stream. They need to have the same exact GOP structure. So make sure "auto I frame detection" is off. You are having two errors one is you GOP structure is off and the other is your bitrate is too high. Check your bitrate through the bitrate viewer and you will see that you will be almost a megabit higher then your original settings. So you may want to lower even further.

BTW Scenarist is the worst program you could use to do multiangle. Unfortunately I do all my multiangle authoring with DVD Studio Pro. It requires the same settings in the encode from CCE but is a little more lenient on the bitrate. Scenarist WILL give you a headache beyond belief.

[PhillipWyllie]

4.4 DVD Video multiangle

If DVD Video multiangle is selected, the encoder outputs a video Elementary Stream for multiangle DVD. Multipass CBR is recommended as encoding mode. It is equivalent to selecting the following three options at the same time.
• Close all GOPs
• Disable auto I frame insertion
• Equalize each GOP’s bit length.

Yes Scenarist is a pain in the bottom when it comes to multi-angle.

[galinette69]

Hi all,

bbjay : my max bitrate is not higher than 3600kbps (I will check it again), and what is very strange is that scenarist issues an error with 3402kbps. All is closed GOP, Auto I frame insertion disabled, and fixed gop structure. I really do not think that bitrate is really the issue, as the limit for dual-angle is 8000kbps PER ANGLE. I really think scenarist is buggy there. If I do not try to do partial multi-angle (the whole movie has a second angle, and not only parts) with the same encoding settings scenarist works well then.

I also ensured that all transitions between single-angle and dual-angle are aligned on GOPs (12 frames multiple) so that there is no uncomplete gop at the join.

I tried with DVDMaestro, with the same encoded files, and this works like a charm. I may give DVD Studio Pro a try, as DVDMaestro cannot add a button over a movie (unless you declare the movie as a menu, but you can't do multiangle then)
Can DVD Studio Pro add a button over a movie?

Thanks,

Galinette

[bigotti5]

... as DVDMaestro cannot add a button over a movie..
Maestro can ...

[Arky]

What audio format / audio bitrate are you using?


Arky.

[Arky]

My apologies - re-reading your post, I just noticed you stated that your audio is 448kbps .ac3.

I recommend you compress your audio to a lower bitrate - 192kbps or somewhere in the low 200s.

I've done a great deal of testing with interleaved VOBs of various kinds, and I always make certain to keep my .ac3 audio bitrate well below 300kbps, irrespective of Spec suggestions which might appear to be higher.

Please try this and repost with your findings.

Regards,

Arky.

[mp3dom]

Are you using custom matrices?
Dunno why, but sometimes Scenarist fail the multiplexing (on multiangles) if a non-standard matrix were used so try the defaul matrix and disable the adaptive Q matrix switch.