-surround or -stereo in oggmachine?

[BluDChyLD]

I have a standard 2 speaker setup on my pc, so should I bother using the -surround switch when making an ogg file or just use simple stereo?
Thanks,
BluDChyLD

[DSPguru]

surround

[JohnMK]

For 95% of the people out there, no functional difference between simple stereo and surround exists. Just had to clarify that. You'll never hear the difference yourself. Only people who attach dolby pro logic receivers to their PCs. Rather atypical, and even then it's not clear to me how the receiver can know that it needs to decode the signal a special way. There's been no exhaustive explanation of this to me. Can anyone tell me which kind of audio-out connector and connection is required to output to a receiver? I've asked this question many times before but I'm always brushed off.

First of all, I don't think any sound cards exist today or will exist in the near future that will in software decode your surround files correctly and send them off to their appropriate discrete channels in a 5.1 sound card. Additionally, let's just say you have an analog stereo plug out going from your sound card to your speaker system. In your case, 2 speakers. In mine, a Creative Labs DTT3500 5.1 speaker system w/ Dolby Pro Logic and 5.1 decoder. The decoding box (receiver, I guess) seems to only have an interest in things coming in via SPDIF + AC3. I don't think it even thinks about decoding things coming in via analog stereo input, or even if they're coming in via SPDIF, but not in AC3 format, it won't touch it.

Basically, what I'd like to see, is a list of the possible ways one can get their surround encoded files actually decoded correctly, with a brief description of the physical interconnects used.

[scorchED]

which min. bitrate should we use, if we want to encode an ogg Vorbis surround file from AC3 to get a good quality?
for me, i get a very good stereo-quality with "250" bitrate settings in OggMaschine". For Surround-Sound this setting must be higher , i guess. But how much higher?
i can't test it myself, because i have not 4 Speakers (but a SB 5.1) now. i will buy them later to watch my movies in surround.

thanks

[Sirber]

Min quality is 0, which is ~64 kbps. At this rate, water and wind are metalic. At 0.100, ~80 kbps, the quality is great and there is no metalic effects. Remember that Ogg Vorbis is almost the same quality at half bitrate compared to MP3.

MP3: 256 kbps --> Vorbis: 128 kbps Quality 0.4
MP3: 160 kbps --> Vorbia: 80 kbps Quality 0.2
MP3: 128 kbps --> Vorbis: 64 kbps Quality 0.0

:D

[JohnMK]

More like 3/4.

[RathO]

I Just switched to OGG. :)
I was reading alot of posts in this forum about OGG bitrates and everything, and still wondering why when i select a quality of 0.200 (~90kbps) i still get kinda real low bitrate like the one shown below @ ~58kbps.... heres the info:

My BeSweet Command line:

"c:\BeSweet.exe" -core( -input "c:\Space1999-E06 AC3 T01 2_0ch 192Kbps DELAY 0ms.ac3" -output "c:\Space1999-E06 AC3 T01 2_0ch 192Kbps DELAY 0ms.ogg" -logfile "c:\BeSweet.log" ) -azid( -c normal ) -ota( -hybridgain ) -ogg( -q 0.200 )


BeSweet Logfile:

[00:00:00:000] +------- BeSweet -----
[00:00:00:000] | Input : C:\Space1999-E06 AC3 T01 2_0ch 192Kbps DELAY 0ms.ac3
[00:00:00:000] | Output: d:\Space1999-E06 AC3 T01 2_0ch 192Kbps DELAY 0ms.ogg
[00:00:00:000] | Floating-Point Process: Yes
[00:00:00:000] +-------- AZID -------
[00:00:00:000] | Input Channels Mode: 2/0, Bitrate: 192kbps
[00:00:00:000] | Output Stereo mode: Dolby surround compatible
[00:00:00:000] | Total Gain: 0.000dB, Compression: Normal
[00:00:00:000] | LFE levels: To LR -INF, To LFE 0.0dB
[00:00:00:000] | Center mix level: BSI
[00:00:00:000] | Surround mix level: BSI
[00:00:00:000] | Dialog normalization: No
[00:00:00:000] | Rear channels filtering: No
[00:00:00:000] | Source Sample-Rate: 48.0KHz
[00:00:00:000] +-------- OGG --------
[00:00:00:000] | VBR Quality : 0.200
[00:00:00:000] +---------------------
[00:52:08:480] Conversion Completed !
[00:52:08:480] Actual Avg. Bitrate : 58kbps
[00:05:45:000] <-- Transcoding Duration
Logging ends : 02/02/03 , 09:59:33

So my question is: is it normal to have a so low bitrate?
If not, what should i do?

Thank you

[RathO]

I adjust the quality to 0.450 and here is what i got:

[00:00:00:000] +-------- AZID -------
[00:00:00:000] | Input Channels Mode: 2/0, Bitrate: 192kbps
[00:00:00:000] | Output Stereo mode: Dolby surround compatible
[00:00:00:000] | Total Gain: 0.000dB, Compression: Normal
[00:00:00:000] | LFE levels: To LR -INF, To LFE 0.0dB
[00:00:00:000] | Center mix level: BSI
[00:00:00:000] | Surround mix level: BSI
[00:00:00:000] | Dialog normalization: No
[00:00:00:000] | Rear channels filtering: No
[00:00:00:000] | Source Sample-Rate: 48.0KHz
[00:00:00:000] +-------- OGG --------
[00:00:00:000] | VBR Quality : 0.450
[00:00:00:000] +---------------------
[00:51:56:480] Conversion Completed !
[00:51:56:480] Actual Avg. Bitrate : 96kbps
[00:05:39:000] <-- Transcoding Duration
Logging ends : 02/02/03 , 10:44:20.

Hum... thats the bitrate i wanted but OGGMachine still show me 0.450 = ~140kbps! ???? :confused:

[DSPguru]

read here (http://forum.doom9.org/showthread.php?s=&threadid=15738), and you'll see that i find partial-logfile USELESS.

anyway, you should use one of the normalizing methods (eg.. hybridgain).

[RathO]

BeSweet v1.5b14 by DSPguru.
--------------------------
Using azid.dll v1.8 (b825) by Midas (midas@egon.gyaloglo.hu).
Using Ogg Vorbis v1.0 dlls (http://www.vorbis.com).

Logging start : 02/02/03 , 14:37:45.

C:\BeSweet.exe -core( -input C:\For the Birds OGM Test!\Forthebirds AC3 T02 2_0ch 192Kbps DELAY 0ms.ac3 -output D:\Forthebirds AC3 T02 2_0ch 192Kbps DELAY 0ms without.ogg -logfile c:\BeSweet.log ) -azid( -c normal -s surround2 ) -ota( -hybridgain ) -ogg( -q 0.350 ) -profile( The OggMachine v0.61 )

[00:00:00:000] +------- BeSweet -----
[00:00:00:000] | Input : C:\For the Birds OGM Test!\Forthebirds AC3 T02 2_0ch 192Kbps DELAY 0ms.ac3
[00:00:00:000] | Output: D:\Forthebirds AC3 T02 2_0ch 192Kbps DELAY 0ms without.ogg
[00:00:00:000] | Floating-Point Process: Yes
[00:00:00:000] | PostGain normalize to : 0.97
[00:00:00:000] +-------- AZID -------
[00:00:00:000] | Input Channels Mode: 2/0, Bitrate: 192kbps
[00:00:00:000] | Output Stereo mode: Dolby surround compatible
[00:00:00:000] | Total Gain: 0.000dB, Compression: Normal
[00:00:00:000] | LFE levels: To LR -INF, To LFE 0.0dB
[00:00:00:000] | Center mix level: BSI
[00:00:00:000] | Surround mix level: BSI
[00:00:00:000] | Dialog normalization: No
[00:00:00:000] | Rear channels filtering: No
[00:00:00:000] | Source Sample-Rate: 48.0KHz
[00:00:00:000] +-------- OGG --------
[00:00:00:000] | VBR Quality : 0.350
[00:00:00:000] +---------------------
[00:03:23:936] Gain of 13.0dB had been asserted to file.
[00:03:23:936] Conversion Completed !
[00:03:23:936] Actual Avg. Bitrate : 98kbps
[00:00:23:000] <-- Transcoding Duration
Logging ends : 02/02/03 , 14:38:08.

hope it helps to answer my question...
Hybridgain has been used.

[dTb]

It's quite normal to get lower bitrates than those reported by oggmachine (or besweet as well I guess). At a given quality level ogg vorbis will have a nominal bitrate shown. This is only a rough guide however as due to the nature of ogg vorbis it is only interested in a level of quality as opposed to a set bitrate. As most movie soundtracks can have a lot of silence and are genearlly no where near as demanding as a music cd the average bitrate is often a lot lower than the nominal bitrate.

As to whether or not to use surround or stereo encoded files, I never bother with surround.