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Mpc Quality Settings For Dolby 2.1 Streams, Is the default --quality 5 insufficient?
atom
post Oct 28 2002, 19:03
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Not sure whether this has been addressed before. Had a look through the forums, but could not find anything at first glance.

Something I picked up quite some time ago with MP3 was that the surround channel in a Dolby 2.1 (is that the correct term?) stream contained severe artifacts even with fairly high quality settings.

I experimented with MPC, and found this to also be true to for --quality 5. --quality 6 is significantly better, but I lack the equipment and expertise to truly compare the original with varying quality settings.

My question is: is this reasonable cause for encoding albums at --quality 6 or higher? In my opinion, yes. I have seen mention of other parameters (--ms?) that could possibly provide better stereo encoding (which is where the surround channel data really lives, isn't it?).

Can anyone maybe confirm my findings and comment on whether I'm just being paranoid, or whether it is more appropriate to use other parameters for such streams, in stead of --quality 6?

Note that many albums (especially live shows) seem to have this type of surround channel information; I believe it's either intentional or a side-effect of the way 2.1 decoding interprets the audio.
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Trelane
post Nov 3 2002, 06:51
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I've been using a "poor man's surround system" for awhile now and haven't noticed anything other than what normal difference information sounds like. I use a quality setting of 5 for all my files.

Dolby Pro Logic decoders do a lot of signal processing (100-7000 hz bandpass and some delay) to the surround channel which could sound bad when coupled with lossy audio formats. The poor man's surround system doesn't do any signal processing (other than getting the difference between the left and right channels).

If you want to try it, it's easy to wire. Connect the two surround speaker's negatives together, then connect the front left's postive to the surround left's positive. Connect this to the amplifier and repeat for the right channel. This is a very simple surround system that works very similar to Dolby Pro Logic.
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- atom   Mpc Quality Settings For Dolby 2.1 Streams   Oct 28 2002, 19:03
- - atom   Have done some more reading and testing. A fairly...   Oct 29 2002, 21:46
- - smok3   some rumble: very interesting, did you test any ot...   Oct 29 2002, 23:14
- - floyd   QUOTE (atom @ Oct 28 2002 - 12:03 PM)Note tha...   Oct 29 2002, 23:31
- - atom   A good example of an album with fairly strong surr...   Oct 30 2002, 17:37
- - Gecko   MPC is designed and tuned only for normal stereo l...   Oct 30 2002, 19:14
- - floyd   QUOTE (atom @ Oct 30 2002 - 10:37 AM)My probl...   Oct 30 2002, 22:15
- - atom   Another happy customer :-) Thanks, Gecko. Your c...   Oct 31 2002, 02:05
- - Trelane   I've been using a "poor man's surroun...   Nov 3 2002, 06:51
- - Dibrom   QUOTE (atom @ Oct 30 2002 - 06:05 PM)The funn...   Nov 3 2002, 07:01
- - CiTay   QUOTE (Dibrom @ Nov 3 2002 - 07:01 AM)Maybe s...   Nov 3 2002, 14:45
- - user   Adding --ms 15 in generally to --quality 5 ... 8 ?...   Nov 30 2002, 15:19
- - liekloo   Yes this is a very interesting topic. I do think ...   Nov 30 2002, 16:58
- - CiTay   We surely shouldn't generally append this swit...   Nov 30 2002, 17:53
- - user   I hope, my words above are not misunderstood, plea...   Nov 30 2002, 18:03
- - CiTay   Got an email from Frank Klemm (you too, user, thx)...   Nov 30 2002, 23:20
- - ssamadhi97   i don't like the term "stereo imaging...   Nov 30 2002, 23:42
- - CiTay   You are right, "surround information" th...   Nov 30 2002, 23:46
- - user   yes, you are right. I don't know, if Frank has...   Nov 30 2002, 23:47
- - user   Adding --ms 15 does not cause artefacts or worse s...   Dec 1 2002, 19:00
- - atom   Hi folks. As is implied in my earlier tests, I DI...   Dec 4 2002, 02:49
- - floyd   hmmm, i have about 15 gigs of mpcs (mostly), and n...   Dec 4 2002, 07:42
- - ProtectYaNeck36   please correct me if i am wrong but, just because ...   Dec 4 2002, 08:04
- - David Nordin   Uhm.. Dolby Surround is just 2 channels where you ...   Dec 4 2002, 08:38
- - floyd   QUOTE (ProtectYaNeck36 @ Dec 4 2002 - 01:04 A...   Dec 4 2002, 23:34
- - Mr. Superbad   I believe NIN's broken was made with DPL in mi...   Dec 5 2002, 00:04
- - atom   After considerably more searching than I anticipat...   Dec 5 2002, 02:59
- - floyd   I agree with you there. Movie soundtracks likely ...   Dec 5 2002, 03:40
- - user   QUOTE (floyd @ Dec 4 2002 - 11:34 PM)QUOTE (P...   Dec 5 2002, 09:24
- - atom   QUOTE (user @ Dec 5 2002 - 12:24 AM)hmm, have...   Dec 9 2002, 03:27


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