[mythtv-users] Capture to DV or "uncompressed" AVI instead of
gcasillo at insightbb.com
Tue Apr 5 23:49:34 UTC 2005
On Tuesday 05 April 2005 07:30 pm, Ian Trider wrote:
> On Apr 5, 2005 3:44 PM, Gregg Casillo <gcasillo at insightbb.com> wrote:
> > Is it possible to capture to DV or "uncompressed" AVI instead of MPEG-2?
> > I understand that these file types are massive, ~13GB/hr. I don't care.
> > For me drive space is less problematic than file manipulation. I also
> > know that this would mean a different capture card. Again, no problem
> > there. I'll shell out anything to get away from MPEG-2 source files.
> Sorry, no -- the PVR-250 only puts out compressed MPEG-2. It -MAY- be
> possible to get raw YUV2 (i.e. uncompressed, raw, video) out of it but
> nobody really has much of any idea yet how it works -- search the
> ivtv-devel archives if you want more info.
I know the PVR250/350 cards are "smart." I.e., they do hardware MPEG encoding
(and decoding in the case of the 350). I need a "dumb" card, a frame grabber
card of some sort that uses the bttv driver, then do the encoding in
> BTW, essentially if the problem you are referring to is audio sync, it
> is because of how the PVR-250 outputs streams -- the video and audio
> are aligned with via the PTS data, essentially timestaps, which
> dicates the temporal relationship between audio and video in an MPEG
> elementary stream. If something bad happens (i.e. a frame drop) the
> PVR-250 takes no notice of it; it will be indicated in the PTS data
> and the player deals with keeping the sync locked together.
> This isn't really wrong, and in fact seems like a good way to produce
> perfectly synced audio (because the temporal position of each frame of
> audio or video is indicated), but because most editing programs simply
> disregard this and work on the raw video and audio streams, you get
> 'issues' -- the lengths won't be exactly the same due to recording
> flaws (like frame drops) and it will go out of sync.
> The way to fix it is to have a program go through and readjust lengths
> of the audio and video so that the raw streams sync properly -- by
> dropping audio or video frames to make the actual video and audio
> streams match the PTS data.
> In Windows, you can do it with PVAStrumento (free) or VideoReDo (an
> excellent MPEG cutter as well, not free, but not expensive). I can
> personally attest to VideoReDo -- it will actually work it out
> automatically -- when it finishes saving a file (you can simply load a
> file and save it) it presents you with a screen that lists any
> adjustments it made.
I've been making use of TMPGEnc MPEG Editor to cut my MPEG files (and demux as
needed for DVD archival). Works well, but for Windows only. Not something I
can build around especially at home, where I'm 100% Linux.
Does anybody encode to MPEG4, edit, then go to MPEG2/DVD? Is this a Bad Idea?
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