[mythtv-users] MythTV 0.27.4: Trouble-free LiveTV with ivtv?

[Nick Morrott]

On 10 April 2015 at 05:04, Frank Phillips <frankalso at gmail.com> wrote:

> Nick hasn't described his problem. It may well be alternating vaapi-ffmpeg
> (introduced before 0.27.2), although there is plenty of room for bugs on the
> analog side. Saul, it looks like, has filed a ticket and bisected his,
> although no explanation has been found.
> https://code.mythtv.org/trac/ticket/12295

I've been looking at a just-refreshed backend system that includes
some DVB-T cards and a PVR-150 connected to a cable box via composite
(and which is the preferred LiveTV input). This machine has been run
as an "embedded" box for several years with zero problems until the
upgrade a couple of days ago. Now running current Debian Stable with
MythTV packages from deb-multimedia.org.

Capture cards have been deleted from the database and have been
re-added, as the system has been updated both in terms of kernel
version and MythTV version. All recording profiles for the PVR-150
have the same contents (720x576 for PAL, 192kbit audio, ...).

Starting LiveTV (defaulting to ivtv-based input) results in about 0.5s
of audio, a frozen picture on the screen, and then silence. The
recording file is still being written to. If I pause the playback for
2-3s and then resume, playback corrects and LiveTV proceeds normally
until the next programme transition.

The local frontend log includes (default logging) warnings about
waiting for buffers when starting LiveTV (and an unknown audio error),
which agrees with the new behaviour I'm seeing - it seems to be
starting playback too quickly. Transitions between programs during a
LiveTV session also fail - the default frontend log output then spews
"Player(1): Waited 10ms for decoder lock" multiple times per second
and the frontend hangs.

There are no issues with LiveTV playback when using a DVB-T input
(either from unpaused PVR-150 playback in LiveTV and switching inputs,
or by removing the PVR-150 from the available LiveTV cards in
mythtv-setup, restarting the backend, and starting LiveTV on the
default DVB-T input.

Watching a since-finished recording from the PVR-150 input is fine
(normal audio and video). Watching an in-progress recording also
worked normally when testing late last night.

The ticket's associated commit looks suspiciously connected - I guess
if no-one else is seeing this issue I'll have to have a look at
reverting the changes and seeing if it helps when I have some time.
Definitely a weird one - biggest showstopper in my experience of using
MythTV since 0.16.

Cheers,
Nick