Muxing vbr audio

[FuPP]

I'm looking for a muxing tool that could handle vbr mp2, would enable to specify the beginning and the end of the clip, and file max size (a la bbmpeg).

Does anyone know such a tool ?

Regards,
Fupp.

[htc10825]

If you search the forum hard enough...
You would find I've posted many times concerned with this subjuct.
Brief: No knowing DVD-Player can play such species back.

[FuPP]

I want to use vbr audio for making SVCDs.

I gave it a try using MPEG2Cut for the video part, Besplit for the audio part, and muxing with mplex. It works fine on my Pioneer DV-535, but I'm just looking for an easier way to mux.

PS : I'm probably stupid (I am :D) but I couldn't find any post from you talking about vbr audio :confused:

Cheers,
FuPP.

[htc10825]

PS : I'm probably stupid(I am ) but I couldn't find any post from you talking about vbr audioI can only comfirm :D
In following thread: http://forum.doom9.org/showthread.php?s=&threadid=43126 I've pointed out: "vbr audio will not work with vcd/svcd, at least not for almost every dvd player."
If you get a working player for it you cannot ensure your next player also support it, and the player of your friends...
And we cannot see if your audio is really vbr...

[symonjfox]

The Philips SVCD specs allows the VBR audio in SVCD.

I made some tests and my standalone Philips DVD 723 worked fine, audio always in sinchrony and chapter points were rispected correctly.
The same using PowerDVD.

VCD doesn't support VBR material (both Video and Audio)

[htc10825]

So it is lucky for the owner Philips dvd player in this point. But those players have many limitations of svcd-playback. Many user complained that in this forum.VCD doesn't support VBR material (both Video and Audio)The fact is, thou non-standard but almost all dvd player support vbr video on VCD. Another fact is, in spec. of VCD/SVCD the GOP structure must guarantee that the I-frames occur twice in a sec. But the very most player can handle bigger GOPs.

[symonjfox]

Originally posted by htc10825
So it is lucky for the owner Philips dvd player in this point. But those players have many limitations of svcd-playback. Many user complained that in this forum.
Philips DVD players support standard SVCDs (so NOT XSVCD) and also CVDs. Yes, I know there are some issues when FF REW or chapter skip on (S)VCD but when watchin a disc, it's all right, nice quality of image and sound.
The fact is, thou non-standard but almost all dvd player support vbr video on VCD. Another fact is, in spec. of VCD/SVCD the GOP structure must guarantee that the I-frames occur twice in a sec. But the very most player can handle bigger GOPs.

I know, but I'm sure that a SVCD with VBR audio IS STANDARD, just the total bitrate should never go over 2720 kbs.

Yes, maybe some players may have troubles with such discs, but I think that nowadays and future DVD players, will support VBR audio by default.

[jshumate]

I find this very interesting, but could someone please post a source other than "I know" that says that VBR is legal for SVCD. I looked at a copy of the specs and it says that sound can go from 32 to 384 kbps, but it doesn't say that it can be variable. Maybe I'm wrong, but I would like some hard evidence. For example, I could say "SVCD video can go up to a maxium bit rate of 3500 Kbps", but that's not true. I have often found in the video world that people claim all kinds of things without anything to back them up. Maybe some of you just assumed the specs allowed VBR audio when in reality they do not. I could be wrong about this and I'm certainly willing to admit it, but how about a link to a web page that supports this claim?
Secondly, why would anyone want to do VBR? Unless you have multichannel audio, using VBR will not result in that much of a smaller file and it will add all kinds of potential playback problems. If you really need to save space in SVCD, just re-encode your audio or video to a lower bit rate.

[ompg]

From Philips SVCD technical explanation (sl00811.pdf)

page 3 :

"Two audio streams
One extra audio Mpeg stream has been hadded for a second language. The Audio streams are selectable by the user, and VBR coding is used for a more efficient compression."

page 6 :
"The use of VBR is optional on the disc, but the decoder in the player must support this.
Simple pieces of music demand a low bit rate, while complex sound require a higher one. When VBR is used, the average bit rate correspond to the average sound complexity, but at constant bit rate (CBR) the bit rate is set for the most complex piece of sound. A typical gain is 30 to 40 %"

Ompg.
------------------------------------------------------
http://svcd-hr.unite-video.com (in french)

[symonjfox]

Originally posted by jshumate
Secondly, why would anyone want to do VBR? Unless you have multichannel audio, using VBR will not result in that much of a smaller file and it will add all kinds of potential playback problems. If you really need to save space in SVCD, just re-encode your audio or video to a lower bit rate.

Easy: SVCD has a TOTAL bitrate limit to RESPECT. Wasting a lot of space with audio track, video will result bad. Using a VBR track, it would be possible to reduce the audio bitrate on silent scenes, while increasing it in complex soundtrack, giving overall great quality to the whole SVCD.

Nobody uses it for 3 reasons:
1- DVD2SVCD doesn't support it (so many novice users never use VBR)
2- Toolame has many troubles with VBR, it's still experimental and the bitrate goes from 112 kbs to 384. For example is not possible to create a VBR with average bitrate of 112 kbs (that would be my goal).
3- BBMpeg can't mux it. You must use TMPGENC or another software I don't remember the name :eek:

[Tobytl]

Um, I may be a retarded american, but isnt there something else limiting the usefullness of VBR audio too? Wouldn't you need an mpeg2 encoder that can analyze the audio file, so it knows where the audio bitrate bottoms out and it can ramp up the max bitrate of the video, and where the audio spikes so it can lower the max bitrate? It just seems to me that if you could make a 112 abr mp2 and set the video max to say 2644 that the audio could spike up to 384 at the same time the video could be at 2644 resulting in a total of 3028. Again, im prolly just stupid, but seems like it could be a problem to me.

[symonjfox]

It just seems to me that if you could make a 112 abr mp2 and set the video max to say 2644 that the audio could spike up to 384 at the same time the video could be at 2644 resulting in a total of 3028. Again, im prolly just stupid, but seems like it could be a problem to me.

You're right. You can use ENCSPOT to check the max bitrate of MP2/3 files, so you encode the audio, check the max used bitrate and create the video file (keeping in mind the max allowable bitrate).

But when using Toolame, if you check a -V 10 the max bitrate I have ever seen in 224 kbs (used very few times) but this was a 160 ABR file. Using lastest Toolame, you can't go under the 112 kbs using VBR mode, so the audio file will be too big for my purposes (I prefer better VIDEO than audio). I think that next relases will allow lower bitrates.

Also I asked for MAX BITRATE option (like -B in LAME), so you can create a 112 kbs ABR file using a max bitrate of 128 kbs (for example), this will save more space in silent scenes and giving a decent quality in all disc. This also give us the ability of use up to 2592 kbs max for video (and this will give a good quality).

[htc10825]

but I'm sure that a SVCD with VBR audio IS STANDARD, just the total bitrate should never go over 2720 kbs.That is THE PROBLEM: if you want to keep within the specification and set the maxmal video bitrate to 2720k(av-max) - 384k(audio-max) - 46k(muxing-overhead) = 2290k, such max. video bitrate is definitvely very low for high motion scene!
The attempt to solve this problem ends with a vicious circle(or dilemma):
If you want to increase the max. AV-bitrate(to non-spec ragion), the most player can only perfect play it if you also increase the muxing rate, and this can be donw only in bbMPEg, but bbMPEG cannot mux the vbr-audio, so you must mux it in TMPG, but TMPG mux the a/v stream only in standard muxing rate, the resulted mpeg stream could be played back very jerkyly, so you have to use bbMPEG, but it dosnt support vbr audio...
One of the advantage of SVCD is the two audio tracks. If you want to make a movie svcd with two audio and vbr, the max. bit rate must be much lower... EVERY my DVD-(Movie)rip on SVCDs have two audio tracks, e.g. eng/ger, eng/chn... How many SVCD movies of you are in two languages/vbr-audio? ...maybe some players may have troubles with such (vbr-audio)discs, but I think that nowadays and future DVD players, will support VBR audio by defaultThe fact is, the numberdvd players from asia(such as china, taiwan...) increases more and more rapid in the last years(most sold at 69$-89$ each and with excellent vcd/svcd comatibility, the one sold at 129$ such as cyberhome 505 has better picture quality than many SONY players). The portion of philips/pioneer player will be smaller and smaller... The SONY players do not official support SVCD at all...

Conclusion:
With vbr audio you may save 20 - 30kbps in audio, but run into the danger of get worse playback quality or insufficient playback support of players. It is only a deceotion of oneself for the owner of philips player, which has very bad svcd playbach support.