Scenarist problem - very strange

[DIggedy]

I'm having a problem when I go to multiplex a track in Scenarist... This will look familar to many of you but the strange part is the stream I'm using:

Error: Video or Audio Buffer underflow (dts:11550771, SCR 11550792)
Error: Total bitrate is too HIGH.

Now the weird thing is the bitrate is quite low...
MPEG 2 VBR: Peak :2512 Minimum: 1912
...and the audio track is only a 192kbps DD
Thats it.
I can't understand how this could violate dvd specs.
Any ideas?

[Arky]

What encoder did you use?

What VBV buffer setting did you use during encoding? It is just possible that this may be the cause of your problem.


Arky ;o)

[DIggedy]

Hi Arky I used TMPG for this particular encode, but also tried CCE at the same bitrates and got the same problem...
I've just used the standard VBV buffer settings that are already there, as I don't even know what they do, should they be anything in particular? I'm not at home at the moment and can't check exactly what those settings were unfortunately...

[Arky]

Well, to be honest, it seems unlikely that you would be unfortunate enough to have accidentally used inappropriate settings on BOTH encoders, unless you were specifically attempting to alter the defaults.

I'm not a Scenarist user, but this does still sound like an MPEG-stream problem to me, rather than a Scenarist-specific issue, so I will continue to think this over. However it's 05:12am here, so I'm off to bed now!!!

Good luck, and please re-post if you find a solution.

Just for the sake of helping other forum members in trying to find the cause of your problem, it might be a good idea to post what encoder & settings you used for audio (unless it was a direct-rip stream-copy), and also what version of Scenarist you are using.


Arky ;o)

[Arky]

By the way, this is what TMPGEnc has to say on the topic of buffer under, and overflow:

[[Buffer Overflow:

When more data than buffer capacity is input



Buffer underflow:

data transfer to the buffer is too late, and enough data for one frame has not been sent to the buffer]]


I should point out, though, that this is generally a DEcoding (playback) issue, rather than an encoding issue, although this is set during encoding. Strictly speaking, I would not expect multiplexing to take account of these. Nevertheless, Scenarist quite specifically states that there is a buffer underflow error...

I am confused that you are getting the same problem regardless of whether you use TMPGEnc or CCE-SP. Very weird. Have you set your project to the same standard as your encoded files? (e.g. NTSC for NTSC). Also, have you mixed any file types in any of your VTS's? This might give rise to muxing conflicts too.

Ok, so I'm just brainstorming here, and I'm not afraid to admit it!

SLEEP beckons - my bed is calling me!!


Arky ;o)

[DIggedy]

thanks for the reply Arky. In answer to your question I have not altered the AC3 track, just reencoded the video stream. Something else I forgot to mention that may affect things is that I have downsized the resolution to 352x240 (it is an ntsc source).

[Arky]

Have you attempted to create an interlaced (rather than progressive) MPEG2 encode at this frame size..?

In theory, this should not be permitted by the encoders, but I have to ask, for the purposes of elimination, because the DVD spec does not permit SIF (Standard Interface Format - which is the frame size you have created) to use interlaced frame encoding, and would consequently be rejected during muxing, if not earlier.


Arky ;o)

[DIggedy]

Ahhhh.... well it looks like you've solved my problem Arky... thanx!!!!
As you suspected, yes it was an interlace encode. Because the source was interlace (the deleted scenes from Road Trip) I left them that way... I have yet to work out how to use AVISynth scripts to do deinterlacing so will have to figure it out I guess!
Thanx again Arky you've been a major help.

[Arky]

No problem - if you still get no joy, just let me know, although I must admit I don't have much www. time at the moment, but I'll do what I can to keep tabs on this thread.

Now I really AM off to bed.

Regards,


Arky ;o)

[DIggedy]

Sorry to ressurect this thread from the dead but I have not had time to finish this project lately and only just got back to it!
I assumed because I'd used the 352x240 (ntsc) with interlace that this was my only problem... but sure enough I reencoded it to progressive in TMPG and used the deinterlace filter, but when I've moved it into Scenarist I get exactly the same problem when trying to mux. :confused:
I am using different frame sizes across the entire project (the film is in 720x480 and the extras are 352x240) but I put these into seperate VTS which should allow this (Scenarist will prevent you from adding a track to a title set if it is not allowed).
Even stranger though, I have done 2 tracks using the lower resolution (1x documentary & 1xdeleted scenes) and the documentary seems to mux just fine, but for some reason not the other.
I'm getting so frustrated with this I'm tempted to just dump the extras altogether! I'd like to keep them though as I'm backing up my original which will not play in my standalone (when I eject the disc it gets stuck halfway in the tray and I have to rip it out, scratching it in the process!).

[Arky]

Damn! lol ;)

Ok.... I know this is a bit of a cop-out, but I have to just ask you - have you TRIED using an alternatvie encoder (e.g. CCE-SP). I'm just curious if there is some strange TMPGEnc anomally here, before I start putting my brain into overdrive and losing sleep about your problem again! :D

Also, please post your template here, either as an attachment, or as a direct cut+paste. Specifically, what GOP settings are you using? Are you adding headers for every GOP? Questions, questions - SO many questions... Just post your template please.. :D


Arky ;o)

[DIggedy]

ok thanx Arky I'm typing this from work at the moment so I'll let u know as soon as I have access to my pc...

[clafferty]

Diggedy, did you ever solve this problem as I am having very similar issues... bitrate too high when it's obviously not.

[DIggedy]

Tell me what your settings (resolution, bitrate) are and I'll see if I can help u out

[clafferty]

352x240, 1500 CBR. i think i've tracked it down to scenarist actually getting upset b/c the bitrate drops too LOW.

[clafferty]

i've outlined my problem in this thread...

http://forum.doom9.org/showthread.php?s=&threadid=42769

i even got a new copy of the files from another source in MPEG format... but run into the same problem when i encode it at 1500, 352x240. i'm not sure what to do except give up on Scenarist... which i don't want to do b/c i spent so much time learning it and actually like it now.

any suggestions would be most welcome. thanks!