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| VideoJedi |
 Posted: Dec 15 2002, 06:23 AM |
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Hi! I was wondering if my DXR3 (Sigma Designs Hollywood Plus) or Radeon 64DDR could be used as a mechanism to preview MPEG2 video while editing in Virtualdub. Both cards can do hardware MPEG2 video.. All I want is Virtualdub to use either of these cards for previewing while I edit instead of trying to play the MPEG2 video from my machine using the CPU (PIII 667Mhz). With the higher bitrate video that I rip from my satellite receiver, it stutters on preview playback in Vdub because I suspect VirtualDub ignores the capabilities of these hardware devices. So can Virtualdub be configured to use hardware MPEG2 devices. Or is there a way to trick AVIsynth into using them to bypass the system CPU for preview?
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| minion |
| Posted: Dec 15 2002, 08:16 AM |
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Advanced Member
Group: Members
Posts: 508
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I Can"t really figure out what you are talking about..But maybe this will help..Virtual Dub Is NOT Compatible with Mpeg2 files..It will not play them it will not Load them .... |
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| VideoJedi |
| Posted: Dec 15 2002, 10:02 AM |
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Yeah.. I am having trouble conveying what I mean, so let me try to put it another way:
Say I have an MPEG2 video file. Here's how I work with it currently:
MPEG2 file=>avisynth (mpeg2dec.dll) =>VirtualDub
What I envision:
MPEG2 file=>avisynth=>Hollywood+ decoding=>Virtualdub
Virtualdub is semi-compatible with MPEG2.. just got to use AVIsynth to pass the video into it.
I don't think it is possible to get a hardware based mpeg2 decoder to allow the previewing in Virtualdub, but thought I would ask anyway. Most people don't have stuttered playback with video in Virtualdub.. it is just my CPU is slow (hence the desire to make a hardware decoder board like the Hollywood+ do the decoding).
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| fccHandler |
| Posted: Dec 15 2002, 07:29 PM |
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Administrator n00b
Group: Moderators
Posts: 3961
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I think what you want to do is impossible. VirtualDub knows nothing of MPEG-2, and by the time VirtualDub receives the video, it has already been decompressed by Avisynth and the .dll plugin. They know nothing of your video hardware, so they can't use any built-in hardware acceleration.
You might try Avisynth "DirectShowSource," but it may be slower than what you're doing now.
BTW, VirtualDubMod supports MPEG-2 (I think).
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May the FOURCC be with you... |
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| minion |
| Posted: Dec 18 2002, 12:52 AM |
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Advanced Member
Group: Members
Posts: 508
Member No.: 1027
Joined: 26-November 02
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Virtual Dub Mod supports Mpeg2/Vob But it doesn"t work very well at all.. Very very very very BUGGY.... |
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| jac_goudsmit |
| Posted: Dec 18 2002, 07:37 PM |
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Feeding an MPEG2 source into VDub is possible through an AVI server such as Avisynth. I myself use DVD2AVI and VFAPI to rip DVDs into Vdub.
Your problem with choppy playback happens because VDub is an editor. It is not optimized for real-time operations such as viewing: when the CPU is unable to keep up with the playback of your input file (AVI or MPEG served through AVI), it will not compensate to catch up.
What you can do to improve playback quality, is switch the "Drop Frames When Behind" option on, in the Options menu. At least this will keep the audio going but your video will look like cr@p. When the option is off (and unfortunately it always is, when you start the program), VDub processes all frames during playback, no matter how slow they come in.
The option doesn't influence editing, by the way, so it's safe to leave it on.
===Jac |
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| SynchronousArts |
| Posted: Dec 18 2002, 09:24 PM |
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| QUOTE (VideoJedi @ Dec 15 2002, 02:02 AM) |
What I envision:
MPEG2 file=>avisynth=>Hollywood+ decoding=>Virtualdub
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If I'm understanding what it is you want to do, it whould look more like this:
MPEG2 file=>Hollywood+Decoder=>DirectShowInterface(rawRGB at 30Mbytes/s)=>avisynth=>Virtualdub.
I don't think there are any "Hardware" MPEG decoders that have "DirectShowInterface" or any other mechanism to read the video back as data. And if it does exist, I doubt that your system could process that much data in real time if it is too slow to decode MPEG in software. |
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| odysseus |
| Posted: Dec 19 2002, 06:40 PM |
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| QUOTE (VideoJedi @ Dec 15 2002, 12:23 AM) | | Hi! I was wondering if my DXR3 (Sigma Designs Hollywood Plus) or Radeon 64DDR could be used as a mechanism to preview MPEG2 video while editing in Virtualdub. Both cards can do hardware MPEG2 video.. All I want is Virtualdub to use either of these cards for previewing while I edit instead of trying to play the MPEG2 video from my machine using the CPU (PIII 667Mhz). With the higher bitrate video that I rip from my satellite receiver, it stutters on preview playback in Vdub because I suspect VirtualDub ignores the capabilities of these hardware devices. So can Virtualdub be configured to use hardware MPEG2 devices. Or is there a way to trick AVIsynth into using them to bypass the system CPU for preview? |
The word you're looking for is
COPROCESSOR
You want to hand dvd frames to the card thus speeding up the DVD decoding and hand over the decoded frames to virtualdub. The popularity of coprocessors has declined hugely since you used to be able to get ns32000, AMD29000, 68020 and 4-way and 8-way parallel processing transputer (from Microway) cards for the ISA bus and later the Weitek FPU and the 8080
Nowadays the mpeg cards are the only remaining "popular" coprocessors, and they're not really that good as coprocessors since they are not general purpose but rather a very narrow special purpose.
I've not seen anything that would let you use an mpeg card this way on MS systems, but on Linux it may be trivial (for a skilled programmer : ) ) to get Mplayer/Mencoder and Transcode to do it, since the drivers have a lot of source code available and you may be able to get your hands on frames as they go on and off the card.
UPDATE - I wanted to find out the answer to this, and whether it would be worthwhile to get one of those cards to speed up my dvd encodings (currently I use the dvd2avi -> vfapi -> virtualdub). While the documents suggest that mencoder uses mplayer on the input file (and therefore would use the accelerator card on a DVD) to get its own input, I can't find a document that definitively says this is the case.
I'll keep searching, I think the developer mailing lists don't get indexed by google so I'll search those next, later.
If this could shave off a few hours from a DVD to avi encode that would be awesome.
PS just thinking aloud, since we now have DVD decoding and Xvid codecs open sourced, it may be much better to port all of the encoding and decoding stuff either to Analog Devices SHARC or TI's TMS family. I bet one could do a complete DVD to Xvid transcode in 20 minutes with a $300, 4-SHARC PCI card.
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