Quantcast Why use Joint Stereo vs Regular Stereo? - digitalFAQ.com Forums [Archives]
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05-12-2002, 07:44 AM
reman reman is offline
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Why Joint
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05-12-2002, 11:42 AM
kwag kwag is offline
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Quote:
Originally Posted by reman
Why Joint
This info is from the TooLame MPEG Audio Layer 2 encoder.
But it also applies to the internal TMPGEnc audio encoder.

Stereo
In this mode, the encoder makes no use of potentially existing correlations between the two input channels. It can, however, negotiate the bit demand between both channel, i.e. give one channel more bits if the other contains silence or needs less bits because of a lower complexity.
Dual channel
In this mode, the 2 channels will be totally independently encoded. Each channel will have exactly half of the bitrate. This mode is designed for applications like dual languages encoding (ex: English in one channel an French in the other). Using this encoding mode for regular stereo files will result in a lower quality encoding.
Joint stereo
In this mode, the encoder will make use of a correlation between both channels in order to achieve higher compression. This will enhance the quality of constant bitrate recordings, and reduce the size of variable bitrate recordings.


Your answer is underlined.
That's why I chose it in the template

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05-12-2002, 07:50 PM
reman reman is offline
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Ahhhh! I see! I guess the idea of using a joint ...I mean selecting joint is a good thing
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05-13-2002, 03:29 AM
Luis Luis is offline
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Quote:
Originally Posted by kwag
Quote:
Originally Posted by reman
Why Joint
Joint stereo
In this mode, the encoder will make use of a correlation between both channels in order to achieve higher compression. This will enhance the quality of constant bitrate recordings, and reduce the size of variable bitrate recordings.

kwag
Kwag,

All you say is right. The only thing I would like to add is that in Joint mode, phasing between channels is lost. This means that Dolby Surround tracks (4.0) cannot be decoded properly and the surround effect is lost. If you have a downmixed Dolby surround track, you should use Stereo (good) or Dual Channel (better) to get the expected results (increasing the bitrate, though).

Luis
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05-13-2002, 10:43 AM
kwag kwag is offline
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Quote:
Originally Posted by Luis
Quote:
Originally Posted by kwag
Quote:
Originally Posted by reman
Why Joint
Joint stereo
In this mode, the encoder will make use of a correlation between both channels in order to achieve higher compression. This will enhance the quality of constant bitrate recordings, and reduce the size of variable bitrate recordings.

kwag
Kwag,

All you say is right. The only thing I would like to add is that in Joint mode, phasing between channels is lost. This means that Dolby Surround tracks (4.0) cannot be decoded properly and the surround effect is lost. If you have a downmixed Dolby surround track, you should use Stereo (good) or Dual Channel (better) to get the expected results (increasing the bitrate, though).

Luis
Hi Luis:

Yes you're right. The primary goal was to crunch as much data available in one CD-R. That's why I chose joint. But if space permits, and anyone want's Dolby Surround, then go ahead and select stereo.

I also chose joint stereo because at 128Kbps ( and low bit rates ) the quality is higher than regular stereo. But I am aware that using joint stereo at higher bit rates is a bad choice, because the quality is worse than stereo.

The file will also be a little larger. I don't remember exactly how much larger, because it's been a while since I did the test compressing a movie with joint stereo and stereo for evaluation.

Anyway, thanks for posting the tip, as many users will want to use Dolby Surround.

kwag
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