converting mpa/mp2 to ac3???

[mikeinfwa]

I am using vegas video 3 to capture 8mm tapes.
I render them as dvd product then use Maestro for the authoring.
Vegas outputs the files as.... video = m2v
audio = mp2

Maestro will accept the mp2 files as audio track.
I do get an warning message after compiling that says the audio track
should be "pcm or Ac3".

The burned dvd will play on my home dvd player with the mp2 sound track. Ifoedit says the audio is "mpeg". I tried the dvd in my neighbors dvd player and the audio didnt play. I had to go into the audio setup menu on their dvd player and select PCM audio. this setting allowed the dvd to play with audio on my neighbors player.

My question is:

do i need to convert the mp2/mpa into ac3?? I have the sonic foundry soft encode program that converts wav into ac3.
Do i need to convert the mp2/mpa audio back into wav? or is there a way to make sonic convert the mp2 into ac3?

BTW i tried using besweet with ac3machine and the ac3 file would lock up my standalone dvd player. (some bug with pioneer settops)

the reason i am trying to use ac3 instead of mp2/mpa/pcm is for standalone dvd compatibilty.

thanks,

mike

[RabidDog]

AFAIK ANY DVD player should be able to play mp2 audio as this is the std not ac3 which generally refers to surround sound. Many older (and not so old) films were only recored with stereo ??converting stereo to 5.1 dobly is a bit of a ?? (tragedy) (waste of space) (loss of quality) (waste of time)

[mikeinfwa]

another question...

will stereo from camcorder convert into "true" 5.1?

Or does 5.1 only come from a source that is recorded as 5.1?

mike

[RabidDog]

You cant make a cow into a pig !! there is NOway you can convert stereo into true 5.1 there may be various kudge for some sort of surround sound .
Actually reading your post a 2nd time it occurred to me that when you played your cd on your mates and had to change to pcm this is simply HOw the sound is output from the dvd player so in fact it worked on his player too.

[furball6969]

AFAIK ANY DVD player should be able to play mp2 audio as this is the std not ac3 which generally refers to surround sound

Actually, AC3 is the standard DVD audio format in North America. Mpeg audio is standard in UK. Also, there is such a thing as 2 channel AC3.

I use BeSweet and AC3Machine to make my AC3 files and they work fine. Sucks about your Pioneer player. Pioneer Home theatre equipment is something I will not buy again.

[Cornucopia]

RabidDog is off and furball6969 is close...

DVD specs say:

NTSC should have linear pcm or ac3 as primary audio, with mp2 or dts as additional options.
PAL (originally) said should have linear pcm or mp2 as primary audio, with ac3 or dts as options. After much lobbying by Dolby, was changed to:
pcm or mp2 or ac3 can be primary, with dts as optional.
Just because your or your mates player happens to be lucky to play it doesn't mean it is compatible. Some players WILL NOT play it, cuz that's not the standard for NTSC dvd. Also, just because it is expected for (S)VCD doesn't always mean much. Heck, we all know there are dvd machines out there that can't do (S)VCD. The firmware could easily treat them as separate beasts and decode the one while not decoding the other.
Maestro's warning message could be disregarded for some, but it is there for a reason.

Read my former post about AC3.
It can be Mono, Stereo, Dolby Surround matrixed into Stereo, LCR aka 3ch, or 5 / 5.1 ch. Now with DD EX can be 6.1ch.

Have heard about the inconsistent compatibility of BeSweet ac3 files before, but SoftEncode works a treat! If you rightfully have that I'd stick with that for encoding.

Getting back to one of your original Q's, IIWY, I would re-export audio from vegas as a PCM wav (I'm sure it can do that) and use THAT as the source for your AC3 encode. Better source-Better Quality.

As to mono or stereo --> 5.1, it can be done. But unless you have the right equipment and really know what you're doing, it won't add much if anything and could very well ruin the original mix. It also is an arduous task and is usually not worth the time and energy taken. Plus, there is the tradeoff of #channels per bitrate and the whole quality/efficiency thing. It really makes sense to only do 5.1 encode when you have recorded a 5.1 source through 5/5.1 channels. Similar things can be said of mono-->stereo, or somewhat stereo-->dolby surround.

Scott
(does make cows into pigs at times, and also shines turds into gold for clients)

[mikeinfwa]

thanks for the tips.

I think I'll try this.

1) capture home 8mm into Vegas video
2) render as .wav audio file with vegas
3) render as m2v (dvd) with vegas
4) convert .wav to ac3 with soft encode
5) import m2v and ac3 into Maestro, menus, chapters etc
6) compile with maestro
7) burn with primo or nero

mike

[patrickm]

BTW i tried using besweet with ac3machine and the ac3 file would lock up my standalone dvd player. (some bug with pioneer settops)

the reason i am trying to use ac3 instead of mp2/mpa/pcm is for standalone dvd compatibilty.

AC3 from BeSweet / ac3machine / ffmpeg is NOT really AC3-compliant, though it's close. the pioneer decoder IS looking for compliant AC3, so the bug is really in besweet's encoder, not the player.

[wulf109]

MP2 and AC3 are both compressd formats. File sizes are the same so I assume they use the same compression ratio. AC3 2-channel offers no advantage over mp2. You are going to find that after you go thru the laborious job of converting to ac3 you will have almost inaudible audio compared to mp2.

[patrickm]

MP2 and AC3 are both compressd formats. File sizes are the same so I assume they use the same compression ratio. AC3 2-channel offers no advantage over mp2. You are going to find that after you go thru the laborious job of converting to ac3 you will have almost inaudible audio compared to mp2.

yes, the bitrates can be the same, but not all compression algorithms are created equal... just look at encoding the same .AVI as a 1000kbps MPEG-1 vs 1000kbps MPEG-4. same size, different quality.

anyway, the point of using AC3 is that it's the region 1 standard audio, not .mp2. also, the 'low volume' effects only occur if you incorrectly transcode your data from a 16-bit format into a 24-bit format.

[Ronaldus]

My audio is just stereo captured through my mini DV camcorder at 48 KHz 16 bits. I've been encoding to AC3 at 192 Kbps with Ffmpeg GUI 0.2c because I thought that was supposed to make it more compatible on standalone players and also take up less disc space without losing quality, but after reading about non-compliant AC3 output from Ffmpeg and BeSweet, I'm wondering if maybe I shouldn't use MP2 audio and let TMPGEnc Plus encode both the video and audio from my source AVI? In the end, I couldn't tell any quality difference when comparing the sound of the source material vs. the AC3 encoding.

What I've found is my TMPGEnc M2V and Ffmpeg AC3 encoded DVDs authored with TMPGEnc DVD Author start to play but pause (freeze) every couple seconds when I play them on a new Toshiba or older Pioneer players, but on a new Pioneer and all Panasonic players I've tried they play fine. When the other players get stuck, if I hit fast forward or rewind and then play, it will play for 1-2 more seconds and pause -- 99% of the time without audio but sometimes I get a moment of audio. This happens regardless of the position in the disc (search functions work fine).

Is pausing every 1-2 seconds the expected symptom of a non-compliant AC3 stream on certain players?

I'm going to try more tests, such as using MP2 audio to see if that cures the problem. If anyone knows the answer now, I'd appreciate hearing to save me some trial and error.

[awlchu]

Everyone,

take a few minutes and read this:

http://www.mmbforums.com/modules.php?name=Forums&file=viewtopic&t=4198#24763

The TPMG AC3 plugin is Dolby qualified and should work with *any* DVD player that has the Dolby Digital trademark on it. If it doesn't work, look at your authoring software or burning software first.

[sturmie]

how does SoftEncode compare to the Vegas 5.1 surround plug-in that will also output to .AC3? i'm just curious b/c i've been using that for a little bit now b/c i heard about the problems w/ BeSweet and its .AC3 output. also, i can't seem to find anything on SoftEncode at all.


sturmie

[Cornucopia]

how does SoftEncode compare to the Vegas 5.1 surround plug-in that will also output to .AC3? i'm just curious b/c i've been using that for a little bit now b/c i heard about the problems w/ BeSweet and its .AC3 output. also, i can't seem to find anything on SoftEncode at all.


sturmie

Seeing as how both SoftEncode and Vegas 's 5.1 surround plugin were written by the same company (Sonic Foundry), my guess is that the plugin incorporates code from SoftEncode and has similar, if not identical, features.

Scott

[steptoe]

There is a product called 8mmtoAVI then is designed solely to convert regular 8mm and super 8mm into AVI

Also, if you really want to convert a WAV to AC3, then have a look for Sonic Foundry Soft Encode

I'm not sure if its still officially available, not if there is another similiar product

Basically it can convert a WAV to a Dolby Digital file

[patrickm]

if you're just looking to do stereo 2.0 AC3, get the TMPG plugin. SoftEncode, which is no longer sold, was like $1000. Any 5.1 AC3 encoder is going to be a minimum of $250. The TMPG plugin is like $30. do the math.