TMPGEnc crashes w/big .wav and kbps question!!

[Thumper]

I'm working on Gladiator and am having problems. I processed it with DVD2AVI using the forced film option because it was 99% film. The first time converted it the .d2v file was good, as well as the wav file. However, the .wav file was 1.75 gigs. When I chose audio sort in TMPGEnc it caused a fatal exectution error. So I processed again, using a different track. This time the file size was the same, but this one worked. So I took a look at the each of the .wav file properties and this is what I found.

Firt track that TMPGEnc wouldnt except.
1.75 gb .wav 488kbps at 48 khz

Second tract that worked.
1.75 gb .wav 192 kbps at 48 khz

So, my guess is that the kbps rate is the hitch. So does TMPGEnc have problems with .wav files processed at that high of a rate? Also, is there a difference between quality of the sound concerning the two .wav files mentioned above.

Thanks in adavance for any feed back.

Cheers. T

[Thumper]

Ok I will answer my own queston. VCD and SVCD's both have a maximum allowable level of Kbits for audio streams. According to doom9.org, the max is 224Kbits/s. Hence, when I was trying to process my .wav file that was 488Kbit/s it cause a application crash. So now I know. Thanks Thumper :0

[poopyhead]

hey thumper...i find your posts a little bit confusing

1) both .wav tracks r exactly the same size? you sure about that? kbit/s means kilobit/sec of audio...hence, 448 kbit/s will have higher filesize compared w/ 192 kbit/s (sorta like higher video bitrate will give a bigger dvd rip file)

2) i ripped the gladiator w/ track 1 (i believe...but it was a looooooooong time ago) with no problems...a way to get around large .wav files is to separate the vobs into 2 groups and process/encode them like 2 separate movies and merge them together later if you want (but i don't think i did that w/ gladiator...i believe tmpgenc allows .wav files upto 2 gigs)

3) the standard is 224 kbit/s for SVCD..that's correct, but even if you input a higher kbit/s .wav file, the mpeg layer II audio file will be converted to 224 kbit/s automatically by tmpgenc (so it doesn't matter what kbit/s of the source .wav u put in there is...cuz it will be converted to 224 kbit/s in the end anywayz)

4) keep in mind about the quality of the .wav file...448 kbit/s >>>>> 192 kbit/s

[Thumper]

poopyhead-Yeah, if I view the details of the folder of which all files of the movie is in, there is to .wav files. The first one which I believe was track 2, and the second one which was track three. Infact DVD2AVI adds its own naming scheme to the end of the name I gave the wav files.

...temp\Gladiator_The_Movie_AC3 2to_ch 488kb/s 48 khz

and the same thing for the other. When I look at the properties it says they both are exactly the same size?!?! Who knows, I've made a good number of these and have never ran accross this. But since it accepted the .wav file that was only 192kbit/s I assumed that it was not due to the size but the difference in the kbit/s of each file. I dont think I've seen a AC3 file that had that high of kbit/s.

In terms of sound quality, I assume the Kbit/s the better?

Maybe it was just a fluke occurance in DVD2AVI!!
Thanks for the feeback. Cheers.

[stanwebber]

the .wav filename kbps info refers to the properties of the original .ac3 track(.wav is an uncompressed format). 488kps is likely the dolby digital 5.1(6channel) track; 192kps is dolby digital 2.0(4 channel pro-logic). if given the choice, the dolby pro-logic track is the best choice for vcd/svcd. dd 5.1 requires extra work to downmix 6channels into psuedo 4channel pro-logic. it's doubful this will ever equal the work done on the dd 2.0 track with professional equipment. svcd accepts 34-384kbps stereo bitrates & up to 4mono or 2seperate stereo tracks. 224kbps is standard for vcd only(2 mono or 1 stereo)

[Thumper]

Thanks stanwebber - Now I think I have a good handle on this topic. Makes more sense. So TMPGEnc crashed probably because It isnt set up to handle 5.1 (6ch track). Yup, just looked at the .ifo file, the first track I processed was indeed 6 channel. Good, learned something new, not to use tracks with those properties until I gain a better grasp on this.

Damn, just went to your website with the guide, little over my head for right now. How in the hell did you learn all these fine details about all this stuff?

[stanwebber]

tmpgenc crashed for some unknown reason. a wav file is a wav file is a wav file (i.e. l+r audio channels). dvd2avi took your dd 5.1 track & threw away the seperate center + subwoofer + 2rear channels to get a 2channel l+r stereo track(dolby surround downmix merges the extra channels into a pro-logic format). dd 2.0 needs no downmixing because the center + 1rear channel is masked inside the l+r stereo channels. the point of my guide is you dont need to think to use it. barring alternate methods, most decisions are taken out of the reader's hands. still, lots of potential problems remain un-addressed so i'm looking to follow sefy's lead & add troubleshooting sections

[poopyhead]

hrm...if that's true stanwebber, i've had a few cases where the 192 kbit/s track produced crackling noises during high pitched sounds...when i switched to higher kbit/s track, those crackling noises dissappeared...if it's harder for dvd2avi to process the higher kbit track, how come it's the lower kbit (192 kbit/s) track that has more problems?

[stanwebber]

did you evaluate the .wav or encoded .mp2? if the former did you downmix? pre-scale decision? normalize? if the latter did you encode stereo or joint-stereo? encoder? sampling rate converter?

[Sefy]

I kinda disagree, all my movies i do with DD5.1 track, i never use the DD20 track (you can even see that in the guide) and I don't have cracking sound or any other problems with the WAV file, and the movie in the example is long enough to create a problem (2hrs30min).

[stanwebber]

there's no harm in using the dd 5.1 track. the arguments i offer against it are quite minor points. of course if you're not interested in retaining the surround sound & go joint-stereo then none of this matters anyway. this discussion caught my attention enough to devote some small attention to this topic in my guide. the dd 5.1 vs 2.0 chart is oversimplified, but it may help to illustrate my points better

[Sefy]

Actually I don't use the Joint_stereo, I use the Dual Channel Stereo, and as for surround, my DVD Stereo System plays it in full Dolby Pro-Logic surround so i believe the surround depends on your audio system too.

[vitualis]

I'm on the camp that believes that you should use the DD2.0 soundtrack for conversion to VCD if available.

To make the DD2.0 soundtrack, the studio would have already downmixed the discrete surround sound (in whatever format) to the Dolby Surround signal -- using Dolby authorised hardware. Furthermore, studios may tweak the DD2.0 soundtrack so that it actually sounds better on Pro Logic decoders.

The 5.1 soundtracks are always tweaked so that they sound best on a 5.1 system. Although you can convert this to a Dolby Surround signal during conversion, it is difficult to believe that the non-Dolby authorised software could ever do a better job than the studio mastering.

The gist is, software conversion of 5.1 --> Dolby Surround stereo can only ever be as good as the studio mastered one. Thus, IMHO, it makes more sense to use the Dolby 2.0 track when available.

Now, this may make little practical difference in terms of the actual sound quality, but I believe best practice should be to use the DD2.0 track when available.

I personally don't use DVD2AVI often but FlaskMPEG. I have experienced "crackling" with the DD2.0 soundtrack but only if you leave the 5.1 --> Dolby Surround downmix option on. If you are using the DD2.0 soundtrack, make sure you turn off this off (as it isn't needed anyway). Perhaps there is a similar issue with DVD2AVI?

@ Sefy, is there any reason why you are using Dual Channel? Dual channel means that exactly half the bitrate goes to the right and left channels. This is a relatively inefficient way for MPEG audio to work. Ordinary stereo (MS Stereo) can allocate a greater share of the bitrate to whichever channel "needs" is more and is probably the best option.

I personally don't use joint-stereo either because for "theorectical" reasons (? possible loss of stereo separation). However, generally the only use of Dual Channel is when you have two separate mono tracks (e.g., different language on each). Even then, MS stereo is still probably better.

Regards.

[Sefy]

@ Vitualis from my personal experience and testing, on my system, the Dual Channel Stereo came out as Dolby Pro-Logic and also sounded much better then both the regular Stereo and the Joint-Stereo (which I avoid at any cost).

I'm not saying this is best for everyone, i'm saying for me, from my testing (same movie encoded in each audio method) the Dual Channel provided the best Surround on my Pro-Logic system.