[mythtv] Ticket #8631: Treat cutlists like lossless transcoding

Jim Stichnoth stichnot at gmail.com
Sun Nov 28 01:35:22 UTC 2010


On Thu, Nov 25, 2010 at 11:13 PM, MythTV <mythtv at cvs.mythtv.org> wrote:
> #8631: Treat cutlists like lossless transcoding
> ------------------------------------------------+---------------------------
>  Reporter:  Jim Stichnoth <stichnot@…>          |           Owner:  mdean
>     Type:  enhancement                         |          Status:  assigned
>  Priority:  minor                               |       Milestone:  unknown
> Component:  MythTV - General                    |         Version:  Unspecified
>  Severity:  medium                              |      Resolution:
>  Keywords:                                      |   Ticket locked:  0
> ------------------------------------------------+---------------------------
>
> Comment (by markk):
>
>  I'm going to go 'on record' and state that I don't think this patch should
>  be committed.
>
>  Firstly, I personally find it counterintuitive to display a different
>  program duration (or position) from the actual, known value. The potential
>  for confusion is huge.
>
>  Secondly, any confusion can only be mitigated by themers competently using
>  the extra information available. Given that this is only likely to be a
>  niche feature, I can see few themes actually doing that.
>
>  Finally, it adds a level of complexity to the playback code that we could
>  really do without. We are trying to make this code simpler and more
>  understandable and the 'cost' here does not outweigh the 'benefit' in my
>  opinion.
>
> --
> Ticket URL: <http://svn.mythtv.org/trac/ticket/8631#comment:5>

I disagree about the intuitiveness of the display.  If I edit the
program, I think it makes perfect sense for it to appear that the cut
sections are actually gone.  In fact, if I go on to transcode the
recording, exactly this happens.  I'm admittedly biased, but I *love*
that I don't have to guess how much of the program is remaining.

I partially agree about the theming issue.  While it's trivial for a
themer to use the appropriate strings, it does require particular
keybindings for full consistency, which the themer currently has no
control over.

As for code complexity, this patch only provides a cutlist-based
mapping between frame numbers and display times or relative seek
times, and doesn't touch what I thought is the underlying complex
code, e.g. AVFD.

I realize I don't have much say, but before closing this ticket, I
would make a suggestion, using #9109 as a motivation.  The solution to
#9109 introduces a new inconsistency: in recordings with varying frame
rates, seeking is no longer consistent.  E.g., jumping forward 10
minutes may end up jumping only 8 minutes, or perhaps 12 minutes.  To
get consistent time display and seeking, myth needs to maintain a list
of frame rate changes in a recording.  This would presumably be done
during recording, or in something like mythcommflag.  Once this list
is available, a cut region could be treated as a section with a frame
rate of infinity.  In other words, if #9109 is extended to provide
seeking that is consistent with proper time display, then cutlists can
be easily folded in.

Jim


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