*AC3 padding?

[Boost]

I would like to burn some AC3s on CDs as audiocd. The dvd.box.sk method is not quite correct. I've downloaded some ac3s from our swedish national radio but they are padded up to cdaudiospeed. They have encoded the material in 640kbps and then padded it up to ~1300kbps to comform with CDAudio. Finally they have stacked a RIFF WAVE header on to the stream so that they can be burned with ordinary cdrecording programs.

I would like to know if there exist a free tool that pads the AC3-stream just like that.

[Snike42]

I've been wondering if this was possible so I tried the guide on http://dvd.box.sk/indexN.php3?pid=guides&s=ac3-1 and it actually works!

There is something strange though. On my dolby digital decoder there's no indicating that it recognises a dolby digital signal. But the sound is comming seperate from all 6 channels.

I think the wav file made by softencode misses some kind of signiture that tells the decoder what kind of signal it is.

I also wonder how they make those dts-audio cd's, anyone?

Snike

[DarkAvenger]

If you don't care that it sounds a bit slower, use HeadAC3he to do this.

[Snike42]

He, I didnt' knew it could do that too!

I tried it, but indeed the sound is too low in pitch. It's fun though!

Anyway, I found out that my DVD player can play AC3 files if I just copy them on a CD in ISO mode!

Snike

[Boost]

I too got it to work after reading exactly what to do. Resampling the material to 44100 and saving as Dolby Digital WAV almost did the trick. As cdrecord (I have my cdrecorder in a Linux boxen) said inapproperiate compression or something like that I had to strip of the RIFF WAVE header and create a new one and did this with sox (I think it's available for Windows too... I have it both for Amiga and Linux).

sox -twav -sw -r44100 -c2 ac3.wav -twav -sw -r44100 -c2 out.wav

That did the trick of writing a new ordinary header to the file w/o messing up the contents.

I did have some troubles playing a stream encoded in 640kps with a LFE channel. I had to lower the bitrate a bit for it to play nice and chopless.

[DSPguru]

Originally posted by Snike42
I found out that my DVD player can play AC3 files if I just copy them on a CD in ISO mode!

Snike

what DVD player do you have ?

[Snike42]

I have a Hiteker BI-660. This is the european version of the well known Apex 660.

It's really a wonderfull machine, it can play almost everything from a normal ISO9660 cd like mp3, mpg, vob and ac3 files.

I even got it to play a mini-dvd, but I had to flash another firmware version from a different type of dvd-player. Flashing the firmware is just a matter of burning it onto a cd and insert it in the player!

Snike