[mythtv] [mythtv-commits] Ticket #1219: LiveTV takes a while to start, and video jerks forwards

Mark Buechler mark.buechler at gmail.com
Wed Feb 8 17:51:10 UTC 2006


I don't think it's a revision or compiler problem. I've seen this behavior
ever since I started playing with DVB in r7607. I've never bothered tracking
it down though. I assumed each time the frontend was waiting for something
in the stream to start playing. Sometimes livetv/channel change is quick,
other times it's 10-20 seconds. If I look at the backend log each time the
pause happens is in the exact same time. At the time of the pause neither
the frontend, backend nor mysql processes are taking that much CPU. For
example:

2006-02-08 10:10:09.711 DevRdB(1): buffer size 32900 KB
2006-02-08 10:10:09.712 DVBRec(1): Resetting Demux Filters
2006-02-08 10:10:09.712 DVBRec(1): Adding pid 0x1422 size(3600384) type(2)
2006-02-08 10:10:09.733 DVBRec(1): Set demux buffer size for pid 0x1422 to
3600384,
                        which gives us a 1500 msec buffer.
2006-02-08 10:10:09.734 DVBRec(1): Adding pid 0x1423 size(94208) type(6)
2006-02-08 10:10:09.734 DVBRec(1): Set demux buffer size for pid 0x1423 to
94208,
                        which gives us a 1500 msec buffer.
2006-02-08 10:10:09.735 DVBRec(1): Adding pid 0x1425 size(94208) type(7)
2006-02-08 10:10:09.735 DVBRec(1): Set demux buffer size for pid 0x1425 to
94208,
                        which gives us a 1500 msec buffer.
2006-02-08 10:10:09.753 PID 0x1422 Found Payload Start
2006-02-08 10:10:09.806 PID 0x1423 Found Payload Start
2006-02-08 10:10:09.898 PID 0x1425 Found Payload Start
2006-02-08 10:10:10.567 TVRec(4): ClearFlags(kFlagWaitingForPayload,) ->
RunMainLoop,CancelNextRecording,AskAllowRecording,SIPa
rserRunning,RecorderRunning,RingBufferReset,
0: start_time: 5859.060 duration: -9223372036854.775
stream: start_time: 65100.668 duration: -9223372036854.775 bitrate=0 kb/s
2006-02-08 10:10:12.668 AFD: Opened codec 0xa9604e30, id(MPEG2VIDEO)
type(Video)
2006-02-08 10:10:12.668 NVP: Disabling Audio, params(-1,-1,-1)
2006-02-08 10:10:12.668 NVP: Disabling Audio, params(0,-1,-1)
2006-02-08 10:10:19.592 TVRec(4): SetFlags(FrontendReady,) ->
FrontendReady,RunMainLoop,CancelNextRecording,AskAllowRecording,S
IParserRunning,RecorderRunning,RingBufferReset,

<long pause here>

2006-02-08 10:10:20.171 MainServer::HandleAnnounce Playback
2006-02-08 10:10:20.171 adding: pc4 as a client (events: 0)
2006-02-08 10:10:20.177 MainServer::HandleAnnounce FileTransfer
2006-02-08 10:10:20.178 adding: pc4 as a remote file transfer

I don't know if this helps in anyway. As I said, I've never investigated it.
I'm using a 2.4.27 kernel gcc 3.3 frontend (AMD64 3200+) and a dual 933 PII
2.6.14 gcc 4.0 backend.

Could it be that the frontend is waiting for a seqstart before decoding the
stream?

- Mark.

On 2/8/06, MythTV <mythtv at cvs.mythtv.org> wrote:
>
> #1219: LiveTV takes a while to start, and video jerks forwards
>
> -------------------------------+--------------------------------------------
> Reporter:  mythtv at biased.org  |        Owner:  ijr
>      Type:  defect             |       Status:  closed
> Priority:  minor              |    Milestone:
> Component:  mythtv             |      Version:  head
> Severity:  medium             |   Resolution:  invalid
>
> -------------------------------+--------------------------------------------
> Changes (by danielk):
>
>   * resolution:  => invalid
>   * status:  reopened => closed
>
> Comment:
>
> Closing as [invalid].
>
> There is nothing reproducable in this report, and the report also does not
> contain the revision that caused the problem.
>
> Mark, open a seperate 0.20 enhancement ticket for the audio stuff.
>
> Biased & co, you need find the revision where this problem started. Or, if
> you changed compilers (gcc 3.x to gcc 4.x say), try reverting the
> compiler. It is possible that some new optimizations in your compiler are
> hurting performace; I've done some benchmarking here and playback
> performance has improved in the last couple months.
>
> --
> Ticket URL: <http://svn.mythtv.org/trac/ticket/1219>
> MythTV <http://www.mythtv.org/>
> MythTV
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>
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