Probs with AC-3 on CD (DD5.1 via SoftEncode)

[kinonet]

Hi there,

first: Thanks to everyone for these inspiring threads. I learned so much out of it without even bothering to ask anyone else. Big hug to all you "maniacs" out there

But now to my problem:

Following the guide for DD5.1 on Audio-CD (e.g. found on dvd.box.sk or digital-digest) using mostly softencode to produce a 44.1/DD.wav track with 5.1 channels in it.

Worked fine sofar. My DVD-Player (an early Pioneer 505) puts out the track to the Onkyo (set-top) DD-decoder which lights up all 6 channel indicators "perfectly"...

BUT: The sound comes out stutterted (channel lights flashes in same rythm) like the data stream is breaking every few milliseconds.

The DD.wav is definetly 44.1 and the mono-channel-wavs for each channel are absolutely ok. (tried even selfmade testtones from cooledit)

I am confused that the dd.wav is always the same size no matter what kind of encode-settings in softencode i choose. I expected the size to shrink when i omit channels and drop in resolution (tried from min to max 640k) --> nothing helped.


Unfortunately i don't have a chance to check the dd-cd with other equipement.

So this is my call for help/suggestions/comments on this procedure.

My aim is clearly to produce a 6 channel encoded Dolby Digital Audio CD. I checked the forums and other resources on the net, but this is not as good documented as one should think. (or did i miss something )

well, anyway, have a great holiday season
(only a few days to go and Santa will give me great new toys like an A03 and a lots of DVD-RW <yipiiiee> )

thanks
kinonet

[DSPguru]

BUT: The sound comes out stutterted (channel lights flashes in same rythm) like the data stream is breaking every few milliseconds

possibly data was interleaved within 5644bytes blocks instead of 6144. that would keep the music speed correct, but will add stuttering noise.

if you have HexEditor, you could check to see where zero padding ends (before address 6000 or after).

I believe DarkAvenger might know more about it.

I am confused that the dd.wav is always the same size no matter what kind of encode-settings in softencode i choose. I expected the size to shrink when i omit channels and drop in resolution (tried from min to max 640k) --> nothing helped.

it will ALYWAYS take 1411200bits/seconds. that's the CDDA format, and it doesn't matter what payload it holds (lpcm/ac3/dts).

[kinonet]

wow, thanks for the very fast reply.

Thanks for clearing the mist around the filelength-"mystery". I should have known it (well where is my donkey-hat )

I checked each of my resulting test dd.wavs for the zero-paddings.
Each data-block is padded to a total length of exactly 6144 bytes.
Rechecked on different file-positions just to make sure i don't make dump readingmistakes.

So it looks like the padding is right (if i did understand it right: 6144 is ok, lower is not ok)

I even tested with things like motorola-order or intel-byteorder in softencode, so whatever i change (or not change) it will result in the same thing.

I found a way to use another "reader". I will use the digital output of my Pioneer LD-Player to be feed into the DVD-Digital-in of the decoder. So the "CD-Audio"-Stream should reach the decoder. With this test i could proof that it's not simply the dvd-player. But this will take extensive reconnecting, so more on this test tomorrow.

Thanks again to DSPguru for your fast advise.

have a good one
kinonet

... you know i'm principially a fan of 44.1 KHz ( ) but doesnt AC3 5.1 DD have to be 48 KHz in any case ?

[DSPguru]

the standard supports 32khz,44.1khz,48khz (just like mp3).

[kinonet]

Good afternoon everybody.

I rechecked the the files for the header and framepaddings. All is absolutely to the norm. 6144 byte each frame (zero padded). The WAV Fileheader is exactly the same as on a 2-channel-pcm-testtone-wav made with cooledit.

On all files the length is 10sec of a440 testtone (in the DD5.1 the lfe is -10db on lfe to secure my subwoofers

The resulting length from the pcm-wav differs from the dd-wav by 6 Bytes, so i would think that i can't be any kind of unsufficient data-delievery-speed from the dvd-player. The player should be able to hold the single-speed-audio-cd-stream at any time. The dd5.1.wav file isn't any longer so the player shouldn't have any problems with reading and delievering it in realtime.

I will make up another test-cd to go to a shop tomorrow to see how other amps react on these streams. Hopefully i'll find a way so i can document it in a foolproof howto.

Any other suggestions or ideas on what to check or test?

Thanks and regards
kinonet

[DSPguru]

did you check the quality of the waves you're inputting Soft-Encoder ?

[kinonet]

@DSPguru

yeap...
i think they are ok.

all waves are saved as Microsoft WAV
44.1 mono at 16bit
for each single-channel-wave
(that should be ok, right?)

when importing into softencode the type-dropdown is set on Microsoft WAV. The composed 6channel sound can be heard intact when pressing "play" in softencode. So i presume that they are all ok.

But you just brought up an idea. Instead of opening it as Microsoft WAV, i could try RAW with the appropriate settings (1channel, 44.1)

Gotta try if that'll make a difference (after some hours of descent sleep

I'll give feedback tomorrow about my testtrip to my local hifi-shop and about the result of this new test.

Thanks again
kinonet

PS: something else i just thought about: If i export it to DD.ac3 instead of DD.wav the resulting DD.ac3 file can be played perfectly well, ok and with the right timing via PowerDVD 4xp. So that would be in my opinion another proof that the step up to there are ok and with it the wavs i use.