[mythtv-users] Transcoding SD MPEG2 to H.264---recommendations?

sonofzev at iinet.net.au sonofzev at iinet.net.au
Tue Nov 30 06:41:49 UTC 2010



On Tue Nov 30 17:38 , f-myth-users at media.mit.edu sent:

>    > Date: Tue, 30 Nov 2010 13:46:15 +1300
>    > From: Nick Rout nick.rout at gmail.com>
>
>    > On Tue, Nov 30, 2010 at 7:54 AM,  f-myth-users at media.mit.edu> wrote:
>    > >    > Date: Mon, 29 Nov 2010 13:19:03 +0000
>    > >    > From: "D. R. Newman" d.r.newman at e-consultation.org>
>    > >
>    > >    > On 29/11/10 08:52, f-myth-users at media.mit.edu wrote:
>    > >
>    > >    > > However---the result was unusable.  The activity log was crammed full
>    > >    > > of "audio 192 time went backwards 0 ms, dropped 1 frames" and "video
>    > >    > > time didn't advance - dropped 1 frames" lines, and about halfway
>    > >    > > through the transcode, it suddenly went from claiming it had 20
>    > >    > > minutes to go, to done.  (It also said "sync: got 26887 frames, 60691
>    > >    > > expected", which might explain a thing or two.)  And the result,
as you
>    > >    > > might expect, was a jumpy mess.
>    > >    > >
>    > >    > > I have no idea why this didn't work.
>    > >
>    > >    > One possibility is that the source file contains lots of errors. I
>    > >
>    > > I considered that, but c'mon.  It was just a normal PVR-250 recording
>    > > from an STB.  It plays just fine.  It seems unlikely that every other
>    > > frame (on average) has an error in it.
>
>    > What are you using to play the file?
>
>mplayer.
>
>    > 					 Are you keeping the exact
>    > filename that you were transcoding and then expecting myth to play it
>    > in place of the recorded programme you started with? That won't work
>    > well because the recordedseek table will be up the wop (TM technical
>    > term).
>
>    > Again if you are giving it a new name and plonking it in mythvideo, it
>    > may need a seektable built.
>
>I'm not playing in Myth at all at the moment, since I'm just testing.
>I took a PVR-250 recording that plays perfectly both in mplayer and
>when sent to a PVR-350 (yes, really, that's how I still watch those
>recordings, though obviously if the transcoding works, I'll switch
>to some VDPAU-supporting card that has an S-video output and send
>the results back to my interlaced CRT) and ran it through Handbrake
>with default options, and with some tweaked options when that failed.
>
>In all cases, I got a file that Handbrake said was missing roughly
>(but not exactly) half its frames, and which played maybe 200-500ms at
>a time and then jumped discontinuously ahead by about the same amount,
>forever.
>
>Either I've got a bad build of Handbrake, or it can't cope with ivtv
>files.  (Or maybe only with ivtv files that also have VBI CC data
>in them.  Or it's something else dumb that I'm not seeing.)  Files
>captured in the same exact way have played without incident for me
>that way for years, and on some Windows box as well using whatever
>Windows defaults to playing mpeg files with.
>
>I haven't (yet) tried either non-Handbrake transcoding, or running
>things through ProjectX first (is it scriptable? last I looked, very
>long ago, it looked like it only had a GUI, but I haven't had time to
>check back during this discussion)---this was just my initial report
>of trying the most-obvious thing and having it blow up for no apparent
>reason.
>
>I'm not trying to use VDPAU yet on the mplayer side; in fact, I'm
>calling mplayer with zero args besides the input file (in MKV format)
>to a GeForce 9500 GT (I think---it's either some other nVidia onboard
>video on that machine, or a card I stuck in, but I don't recall and
>haven't checked yet) and it's doing fine---it's not complaining that
>it's too slow to play the result and dropping frames, or anything like
>that.  (It complains it can't open libvdpau, which isn't surprising
>because I've put zero effort into configuring VDPAU on that machine
>yet, and that its using ffmpeg's libavcodec family.)  Of course, it's
>only SD video.  If Handbrake hadn't spewed magabytes of complaints
>about dropped frames and magically finished halfway through its
>estimated time, I'd suspect the player, but at this point I suspect
>the problem is with Handbrake and not playback.
>_______________________________________________


I know I'm jumping in quite late, but have you tried the mythnuv2mkv.sh script..
I've been using it for over a year and it's generally fantastic.. 







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