HydrogenAudio

Lossy Audio Compression => Other Lossy Codecs => Topic started by: mrbruno on 2002-12-29 11:29:24

Title: help ! I'd like to read AC3 files on a dvd player
Post by: mrbruno on 2002-12-29 11:29:24
Hi!

I'd like to know how to read my
AC3 audio files on a standalone
DVD player.

I have ripped many AC3 soundtracks
from movies and I need to play them
on a standalone DVD player, just
like I would play MP3s
(but I don't
want to convert them to MP3s, because
I want to keep the highest quality).

Is it possible ?

Thanks.
Title: help ! I'd like to read AC3 files on a dvd player
Post by: M on 2002-12-29 11:44:39
Sure. The easiest way is to use BeSure (http://www.doom9.org/index.html?/BeSure.html) (this link points to a useage guide; the necessary components, BeSure 1.2 and BeSweet 1.4, can be downloaded from Doom 9 (http://www.doom9.org/index.html?/software2.htm)).

  Caveat: You cannot simply compile a disc of AC3 files, like you would for MP3s. This method requires burning an AC3-audio CD, which is limited to the audio length of your CD blank. The reason for this is that for the DVD player to process the AC3 data, it must be fed to the decoder at a predictable interval... and (so far) the only way to reliably manage this is to encapsulate that data within a WAV/CDA structure. That means if any of your soundtracks are longer than 80 minutes, you will have to split the output over a couple of discs. But the audio output will be identical to the original AC3 source.

    - M.
Title: help ! I'd like to read AC3 files on a dvd player
Post by: mrbruno on 2002-12-29 12:27:55
Yes, I'm aware of this method already.
But it's not what I want to do.

You see, as you said, I'd like to compile
AC3s just like MP3s.  On one CD-R, i can
fit about 5 full movie soundtracks (about 500 minutes of audio
on a single CD-R) !

The only problem is to play them ...

I had this idea : what if I rename the
AC3 to VOB to fool the player ?

There must be a way !
Title: help ! I'd like to read AC3 files on a dvd player
Post by: M on 2002-12-29 12:41:06
Well... with DVDDecrypter (http://www.dvddecrypter.com/) you can use the "Stream Processing" feature to rip a VOB which only contains the AC3 streams. But in order to use this, you would need to go back and re-rip all your soundtracks. If you need to re-compile substitution VOBs, you might be able to garner something from this Doom9 guide (http://www.doom9.org/index.html?/mpg/ifoedit-dvdauthor.htm) on VobEdit and IfoEdit (and an alternate site for these is here (http://mpucoder.kewlhair.com/Derrow/index.html)). I'm afraid I can't offer much more than this, though. Sorry.

    - M.
Title: help ! I'd like to read AC3 files on a dvd player
Post by: S_O on 2002-12-29 12:48:01
Do not use BeSweet & BeSure, it´s going to reencode the ac3 (quality loss)!
You could try to remux and author a miniDVD with IfoEdit, get it from: http://mpucoder.kewlhair.com/derrow/ (http://mpucoder.kewlhair.com/derrow/)
You need to demux the ac3, then remux it with IfoEdit with a mpeg2-video. You could try to encode a picture with TMPGEnc and use it as video.
Even if you are able to create a vaild miniDVD, and your software-player on PC will play it perfectly, your DVD-Player will most likely not play it.

I have no other idea what you could do.

Edit: M was faster
Title: help ! I'd like to read AC3 files on a dvd player
Post by: smok3 on 2002-12-29 16:26:53
check http://www.hydrogenaudio.org/forums/index....t=ST&f=1&t=4249 (http://www.hydrogenaudio.org/forums/index.php?s=&act=ST&f=1&t=4249)
Title: help ! I'd like to read AC3 files on a dvd player
Post by: kheops on 2002-12-29 17:16:38
if you want to keep the ac3 format you would need an authoring program to create a set of vob files and the corresponding ifo files

check this to read more
http://www.doom9.org/mpg/maestro.htm (http://www.doom9.org/mpg/maestro.htm)

what you want to do is definitely possible

+++
Title: help ! I'd like to read AC3 files on a dvd player
Post by: user on 2002-12-29 18:46:52
2 easy solutions:

1. get the right player....

There are players (mainly with ESS chip, I think) which play in a kind of Smartnavi = beta-browser directly from data-Cds *.ac3 files.


Or:

2. Burn a CDDA, with ac3-waves created by HeadAC3he, for example.
Title: help ! I'd like to read AC3 files on a dvd player
Post by: mrbruno on 2002-12-30 18:07:39
Thanks everyone for your replies. I think the best
thing to do is find a dvd player with a "smartnavi"
browser. I don't want to mess with dvd authoring !
Too complicated for me...
Title: help ! I'd like to read AC3 files on a dvd player
Post by: user on 2002-12-30 20:11:39
yeah, if you find a player with Smart-Navigation or so called "beta browser"

3. HTPC ?

I have a third possibility:

use a HTPC (silent PC with good soundcard, digital out eg., and good TVout), play a ac3 file with a software player (hmm, actually I don't know, which one works, perhaps WinDVD ?)



But as ad hoc solution:

Use HeadAc3he for creating waves, which contain the original 5.1_ac3 files.

Burn these waves as regular CDDA (Audio-CD) by Nero or any other burning program.

Every (even old) CD-players or (new) DVDpalyers with digital out can play them.
you need a digital connection to your ac3 decoder.
Title: help ! I'd like to read AC3 files on a dvd player
Post by: S_O on 2002-12-30 22:02:42
Quote
Use HeadAc3he for creating waves, which contain the original 5.1_ac3 files.

That won´t work, I tried it myself, because all ac3 I´ve seen from a DVD have a smaplerate of 48000Hz, but CD has 44100Hz. I tried that myself and I thought great, HeadAC3he outputs 44100Hz wav anyway. The disc could be played but:
- audio-length isn´t showed correctly
- audio is not too slow, but I noticed the audio is quite often interrupted
I played the wav on my pc over S/PDIF out (format-tag changed to 0x92), the same problem. I changed the samplerate to 48kHz (only changed in a hexeditor, not resampled) and it worked perfect, but this 48kHz wav cannot be burned to CD.
I found the explanation for my problem: one ac3-frame always contains 1536 samples per channel.
1536 samples are in wav 16-bit exactly 6144 bytes, because the ac3-frame is smaller the rest of the 6144 bytes in the wav are just zeros. After that 6144 bytes the next ac3 farme in the wav begins.. The samplerate doesn´t matter. If it´s 48000Hz one frame would contain 0,032 seconds, and the 6144 bytes in the wav would also match 0,032 seconds. If it´s 44100Hz it´s about 0,034 seconds and at 32000Hz it´s 0,048 seconds. In wav-file and in the ac3-frame. But what happens when the ac3-frame is 48000Hz and the wav 44100Hz??:
ac3-frame: 0,032 seconds, but in the wav-file it needs the space of about 0,034 seconds! You see that won´t work correctly and in your decoder a buffer underrun appears, because it doesn´t get the data fast enough.
Title: help ! I'd like to read AC3 files on a dvd player
Post by: S_O on 2002-12-31 13:31:46
After writing that I had an idea:
When the decoder doesn´t get the data fast enough because one frame contains not enough samples, I thought, I could make the samples smaller, that means less zeros after the real frame. My calculation: 6144 / 48000 = 0,128 and then 0,128 * 44100 = 5644,8
Hmm.. A frame cannot be 5644,8 Byte big, but mp3 use padding, some frames are bigger than other ones and I calcualted that when I put 5 frames toghether they should have a size of 28224 Bytes (5 * 5644,8) and in this 28224 Bytes the farmes could have not the same length:
5648 - 5640 - 5648 - 5640 - 5648. That are know the framesizes in this 28224 Bytes.
To proof my idea I wrote a program creating such wavs: ac32cd
But warning, I wrote it while watching TV in the evening, so there could be lots of bugs in it. anyway you can get it here: ac32cd.zip (23KB) (http://l.b.oltmanns.bei.t-online.de/ac32cd.zip)
Usage is very simple: ac32cd infile.ac3 outfile.wav
then you have to enter the bitrate, I was too lazy to implement any kind of ac3-analyzing. ac3 file must be 48kHz and 100% sync-error free. For me it works, please try it if it works for you, too. Also check if they are no pops or clicks in it, sound should be 100% perfect.
Title: help ! I'd like to read AC3 files on a dvd player
Post by: mrbruno on 2002-12-31 17:47:36
wow, this time it's getting too technical for me !
I don't even understand if the  result
will be a max total playtime of 80 minutes
(which I don't want, as I said on a previous post).

If so, it's no use for me to try it, sorry !

The "smartnavi" method seems more attractive to
me... I wish I had more skills in digital audio to fully
understand what you wrote !