convert PCM audio to AC3

[low-fat-al]

I have a DVD-9 were the only audio present is PCM. It is too big to encode down to DVD-R. I want to know if it is possible to re-author the DVD and convert the PCM audio to AC3 for space saving and keep the orginal structure with menus and such? The video may need very little encoding to fit on the DVD-R. Any help or comments will be nice.

[wulf109]

Available ac3 converters are poor at best. Compress the DVD twice to get down to 4.37GB's. PCM sound is best for concerts if your interested in the music. When I encounter a concert disk with only ac3 sound I convert it to PCM.

[jeex]

When I encounter a concert disk with only ac3 sound I convert it to PCM.

thats retarded. the only thing you're doing is degrading video quality.

[ZippyP.]

When I encounter a concert disk with only ac3 sound I convert it to PCM.

thats retarded. the only thing you're doing is degrading video quality.

A little harsh on the judgement. What he's degrading is the audio quality.

I guess video as well since you need to compress it alot more b/c of the size of PCM. Either way, leaving it as AC3 is better.

[OkAtanAdam]

The best tools I found were Vegas v.4 and Soft Encode v.1...
Both use DolbyDigital compliant AC3 encoder...

[low-fat-al]

ok, so back the original topic..

So what you are saying is to comress it down once and then again to get it to fit on a DVD-R.

I have used pinacle Instant Copy and DVD-Shrink...

Will that keep the video from looking that bad?


If anyone wants to try the DVD I am trying to do feel free and tell me what you did to get it to work. I am trying the Tony Hawks Trick Tips Vol 2... Vol 1 (1 layer) and Vol 3 (2 layers) worked fine...

[jeex]

When I encounter a concert disk with only ac3 sound I convert it to PCM.

thats retarded. the only thing you're doing is degrading video quality.

A little harsh on the judgement. What he's degrading is the audio quality.

I guess video as well since you need to compress it alot more b/c of the size of PCM. Either way, leaving it as AC3 is better.

i dont think there is a quality loss when you convert ac3 to pcm.

its kind of like converting mp3 to wav..

you lose quality when you convert from wav to mp3, but i dont think you lose quality when you convert mp3 to wav.. i may be wrong though.

[mysticgohan17]

I think jeex means, by converting to PCM, less space is reserved for the video quality.


If i missed something, tell me :P

[bottle-necked]

I have a DVD-9 were the only audio present is PCM. It is too big to encode down to DVD-R. I want to know if it is possible to re-author the DVD and convert the PCM audio to AC3 for space saving and keep the orginal structure with menus and such? The video may need very little encoding to fit on the DVD-R. Any help or comments will be nice.

I've only tried this one time and that wasn't on vob files with more than one audio stream, so you're on your own: Don't come crying to me if it won't work. lol

RIp the entire movie to HDD using DVD Decrypter.

Load each vob in Tmpgenc Mpeg Tools and demultiplex the audio and video streams. Save to an empty work folder.

Convert the audio (pcm to AC3) using ffmpeggui and save to that work folder.

Take the streams (video and ac3 from the work folder) to IFOEdit and "Author new DVD" to create a new vob file. (I would do one VOB at a time here.)

Copy the vob files back into your ripped hdd folder and overwrite the original PCM versions.

Shrink with DVD Shrink as normal and burn.

*Except for converting the audio leave the all other files unmodified.
--------------------
>OR<

Rip with DVD Shrink and >no compression< the DVD to hdd folder and take out all but 1 audio stream. DO as above, then shrink as needed to fit a blank.

You wanted an idea... THere's mine.


Good luck.

EDIT: I don't think the menu(s) are allowed AC3 audio. . .?

[spectroelectro]

First: yes, you can take a DVD with a PCM WAV soundtrack, rip it, demux the elementary streams, and convert the WAV soundtrack to Dolby AC3 using BeSweet with the AC3Machine GUI front-end and then re-author the DVD and it will work just fine. I've done this with my own DVDs made of TV shows, so I know it works.
BeSweet is not 100% absolutely totally compliant when it produces AC3, but I've never yet encountered a DVD player which can't play back the AC3 proudced by BeSweet. YMMV.
As for using DVDShrink -- it's an excellent tool, but ReJig produces even better results. Compressing the elementary video stream with ReJig is incredibly fast (typically requiring no more than 5 minutes or so for a full 4-gig file) and best of all, ReJig introduces none of the artifacts I see when I use DVDShrink. ReJig is simply heads and shoulders above any other transcoding tool I've come across, and best of all, ReJig is freeware.

[low-fat-al]

I am going to try to use the method that bottle-necked mentioned. I use soft encode to encode to AC3. One question. When creating the new VOB files using IfoEdit it noticed it had part on there for chapter info import. Is that needed or the orginal IFO files going to correct that, and with original ifo file used it doesn't it have reference to the audio being a PCM?

By the way thanks for the feedback guys.

[bottle-necked]

My idea of using IFOEdit was only to re-create the vob file, not to use any of the other files the program creates. Those are to be deleted. Just re-create the vob file then copy it back into the original 'ripped' VIDEO_TS folder overwriting the Vob w/PCM audio. Chapter information, menus, etc, is in the original ifo files which you should leave intact.

I would do one vob at a time. I would also test this modified VIDEO_TS folder after the first vob by playing it with like PowerDVD. The ultimate test is of course burning and on a settop box.

I have only did this idea once but on vob files that had only 1 audio stream and then it was MPEG1 Layer2.

But, don't modify any of the original files in the ripped folder, just demux the vobs, convert the audio, re-create the vobs, and copy them back in overwriting the originals. (I would not convert the audio in the menu vobs).

This idea may not work without 'reauthoring' the DVD. Doing that will loose your menus, but is worth a try I guess.

Good luck.

[awlchu]

Available ac3 converters are poor at best. Compress the DVD twice to get down to 4.37GB's. PCM sound is best for concerts if your interested in the music. When I encounter a concert disk with only ac3 sound I convert it to PCM.

wulf109,

The two channel AC3 encoder from TMPGenc AC3 folks works extremely well. Full of options and qualified by Dolby. And all for $29US.

I'm referring to the AC3 encoder sold for their DVD authoring program. You don't need the DVD authoring program by TMPGenc to use this very nice encoder.

Besides, can one really hear the difference between AC3 and PCM on your average home system? Considering everything that happens to the audio from the disk until it reaches the speakers, I really cannot hear the difference. (But I'm not a trained to hear the difference.)

awlchu

[ricky1756]

When you convert a mp3 to a wave, all you get is a big file that still sounds exactly like the mp3, because mp3 uses a lossy codec. the audio information taken out to make the mp3 is lost. the same would hold true for converting an ac3 to pcm

[low-fat-al]

I could not get this to work. I don't know if I did anything wrong.
The total size before I did this is 7.72 gigs and after I converted every audio to AC3 at 192 k it was 5.8 gigs. Well when I open it up in DVD-Shrink it gave me an error when I tried to encode it down. And it was still showing the PCM audio as the audio tracks. I tried to edit the IFO file to tell it now has AC3 tracks and it still didn't work. I am at a loss with this one. Unless anyone has any ideas here.

[ricky1756]

did you sent it through a dvd authoring program first?

[Faustus]

If your going to reauthor the disc then softencode is likely the best. Sadly I dont think sonic makes it anymore.

[jaxxboss]

I have to agree with awlchu regarding the AC3 package from tmpge. Just take the whole ripped video and load it in dvd author and have ur audio set to re encode to ac3, set ur b/r and have at it. Now, u may get a warning that the size will be too big to fit on a dvd, just ignore it. Once authored (20 min), you can then load that back into shrink or clone dvd and bring the size down to where u want it. make sure u get the ac3 version 1.06 as this is the only one that will convert LPCM.

[indolikaa]

I've been using ffmpeg at 256k for AC3 and haven't had any problems...

[low-fat-al]

I guess you guys don't understand....
It didn't work because the IFO file has information on it saying there is PCM audio associated with this DVD. Since I took it out and replaced, it gives me errors tying to load it into DVD-Shrink and Pinnacle Instant Copy. The file size is too big for me to just burn everything after I converted everything too. I need to shrink the video down just a little bit.

[johns0]

To keep all the menus just run it thru dvdshrink as is without replacing the pcm to get it down to the size you need.

[low-fat-al]

I tried that.... when it is loaded into DVD-Shrink it claims it still has the PCM audio. I try to encode the video down to the size I really need (which is about 67%) and it just gives me errors when trying to back it up. IT DOESN'T WORK!!!