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| Cerberus |
| Posted: Jan 27 2003, 11:14 AM |
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Advanced Member
Group: Members
Posts: 100
Member No.: 2031
Joined: 18-January 03
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Hi I was just wanting to know if their an WMA acm engin that i could use for audio on avi files. I know you can encode a WMA file and change the header to a wav file then tie it into the video. I didnt find anything much by seching google for "ACM WMA" so if anyone knows of this or knows its a bad idear please let me know. 
(to take advantage of the latest windows media 9)
Thanks in advance  |
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| jcsston |
| Posted: Jan 27 2003, 05:21 PM |
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Matroska Dev
Group: Moderators
Posts: 553
Member No.: 652
Joined: 3-November 02
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I think WMA in avi files isn't a great idea. Because of the lack of legal ACM WMA encoders and decoders.
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Use the Matroska file format |
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| ChristianHJW |
| Posted: Jan 27 2003, 09:34 PM |
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Advanced Member
Group: Moderators
Posts: 1768
Member No.: 2
Joined: 7-July 02
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M$ has promised a VfW WMV 9 codec recently on Doom9 .. but no mention of a WMA ACM codec ...
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Visit the unofficial Virtualdub support forum on http://forums.virtualdub.org - help to reduce the big number of emails Avery Lee is getting every day !!
Support matroska as container and Gstreamer as the only truely open, x-platform multimedia platform .... |
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| Neo Neko |
| Posted: Jan 27 2003, 11:14 PM |
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VirtualdubMod Alpha tester
Group: Vdubmod Alpha Testing Team
Posts: 474
Member No.: 24
Joined: 11-July 02
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I will have to read again but I believe Amir mentioned WMA ACM as well. But ATM both are vapor ware so no sense holding your breath for now. And even once they are out their portability is limited.  |
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| phaeron |
| Posted: Jan 28 2003, 07:58 AM |
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Virtualdub Developer
Group: Administrator
Posts: 7773
Member No.: 61
Joined: 30-July 02
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Windows Media Audio V1 and V2 both have ACM engines -- that is, in fact, the original form of the codecs as they were used in the Netshow Encoder, before it became Windows Media Encoder. However, the codecs aren't usable in AVI files, because specific unlocking codes must be supplied to the codecs for them to respond, presumably as a licensing mechanism. The incarnations of the "DivX Audio" codec are simply versions of the WMA ACM drivers that have had their authentication checks (badly) disabled; the ID tags (0x0160/0x0161) were never changed, so DivX Audio picks up WMA streams that the real WMA codec refuses to decode.
Audio Compression Manager (ACM) was designed to work with audio formats that have constant block sizes (nBlockAlign), so even if the newest WMAs are ported back to ACM, I wouldn't expect VBR or lossless modes of operation.
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| ChristianHJW |
| Posted: Jan 28 2003, 04:00 PM |
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Advanced Member
Group: Moderators
Posts: 1768
Member No.: 2
Joined: 7-July 02
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| QUOTE (phaeron @ Jan 28 2003, 09:58 AM) | | Audio Compression Manager (ACM) was designed to work with audio formats that have constant block sizes (nBlockAlign), so even if the newest WMAs are ported back to ACM, I wouldn't expect VBR or lossless modes of operation. |
I was just going to add this, but you beat me to it Avery. Maybe one day someone will be able to make a UCI wrapper for WMA and WMV9  ....
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Visit the unofficial Virtualdub support forum on http://forums.virtualdub.org - help to reduce the big number of emails Avery Lee is getting every day !!
Support matroska as container and Gstreamer as the only truely open, x-platform multimedia platform .... |
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| Cerberus |
| Posted: Jan 28 2003, 05:10 PM |
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Advanced Member
Group: Members
Posts: 100
Member No.: 2031
Joined: 18-January 03
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 thanks for youre input much apreciated....  |
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| outlyer |
| Posted: Jan 28 2003, 07:04 PM |
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Spanish Section Mod
Group: Moderators
Posts: 215
Member No.: 1269
Joined: 10-December 02
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| QUOTE (phaeron @ Jan 28 2003, 08:58 AM) | | Audio Compression Manager (ACM) was designed to work with audio formats that have constant block sizes (nBlockAlign), so even if the newest WMAs are ported back to ACM, I wouldn't expect VBR or lossless modes of operation. |
When I red Amir's post I just wondered, now that M$ is giving a second chance to AVI, if they don't plan to extend the AVI specification to support VBR audio. What do you think? Could this be done? Although it could break backwards compatibility but they don't usually care much for old systems...
(whispering) Christian, I think they fear matroska  |
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| fccHandler |
| Posted: Jan 28 2003, 07:10 PM |
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Administrator n00b
Group: Moderators
Posts: 3961
Member No.: 280
Joined: 13-September 02
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(whispering) Just as a curiosity, I remember that msaud32.acm can be unlocked for general use by changing one byte in the file!
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May the FOURCC be with you... |
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| Neo Neko |
| Posted: Jan 28 2003, 08:22 PM |
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VirtualdubMod Alpha tester
Group: Vdubmod Alpha Testing Team
Posts: 474
Member No.: 24
Joined: 11-July 02
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| QUOTE (phaeron @ Jan 28 2003, 01:58 AM) | | Audio Compression Manager (ACM) was designed to work with audio formats that have constant block sizes (nBlockAlign), so even if the newest WMAs are ported back to ACM, I wouldn't expect VBR or lossless modes of operation. |
It may have been designed that way. And that may be how it is supposed to be used. But I know of a few ACM codecs who via one method or another do VBR or ABR. The lame ACM being one of em. Not that it works well.  |
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