[mythtv-users] Lossless Transcode 0.25
Scott & Nicole Harris
snharris99 at live.com
Tue Mar 20 02:10:23 UTC 2012
>>>> Is it just me, or is the lossless transcode in 0.25 RIDICULOUSLY fast?
>>>> I queued up 3 transcodes and by the time I finished editing another
>>>> cutlist for transcode (and I’m pretty quick at blowing through a
>>>> cutlist), all 3 were done.
>>> Of course it's ridiculously fast! It doesn't do much of anything. Aside
>>> from re-encoding up to a few dozen frames for each cutpoint, all you've
>>> got is some very minor container reprocessing, and a file copy. Out of
>>> an hour recording, you're looking at a few seconds worth of video that
>>> needs processing.
>> I don't recall it being that fast previously. In fact, it's why I
>> to use the frontend in our gym as a SBE to offload transcode jobs to
>> they took so long. They took quite some time on the SBE too.
>There haven't been any changes that should make it significantly faster
>or slower. My lossless transcodes have always been disk IO limited
>rather than CPU limited. Offloading to a remote machine that would have
>to pull content off a network share, and push the result back to the
>same network share, would have been all that much slower.
Actually, I have discovered something a little disconcerting. After
watching some shows that I transcoded with 0.25 last night and tonight (some
of them recorded with 0.25 and some on 0.24), there are flashes of vertical
purple lines on the screen approximately every minute and at every
commercial transition that was removed. The same issues are not present
on the recordings before they have been transcoded. I tested playback on 5
different frontends, different recordings, etc and it's pretty consistent;
anything transcoded with 0.25 in the last two days has vertical purple line
flashes every minute or so; everything else is fine.
It sounds a lot like this http://code.mythtv.org/trac/ticket/10110 except
these are lossless transcodes. Also, the same issue here
indicates that an ffmpeg update fixed it for him to the point that the
affected recording were no longer affected, indicating it was a playback
issue. 4 of my frontends are Mythbuntu 11.10 fresh installs and one is a
pretty old 10.04 install that has never displayed this behavior before these
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