[vdr] vdr-xine trickspeed bug report

[Reinhard Nissl]

Hi,

Am 08.04.2011 19:45, schrieb Joerg Riechardt:

> In the replay of a h264 720p recording I am paused at a mark.
>
> 1. Now I press right and start slow motion forward at 1/8 speed.
> The log shows
> TrickSpeed: 8
> TrickSpeedMode: push H.264 SequenceEndCode
> TrickSpeedMode: push H.264 SequenceEndCode
> TrickSpeedMode: push H.264 SequenceEndCode
> TrickSpeedMode: push H.264 SequenceEndCode
> PPPPTrickSpeedMode: push H.264 SequenceEndCode
> PPPPPPPPTrickSpeedMode: push H.264 SequenceEndCode
> ...
> In the rythm of the SequenceEndCode messages I see distortions
> and hold-ups in the video flow. The start is immediate.
>
> 2. This time starting at the mark I press play, pause, right and
> start slow motion forward at 1/8 speed. The log shows
> TrickSpeed: 8
> PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP
> ...
> The start is delayed, but there are no distortions and the video
> flow is steady.
>
> So I guess there is something wrong with the SequenceEndCode
> detection in 1. and in 2. with the delayed start.

You describe slow backward and slow forward behavior of VDR (and 
vdr-xine behavior in case of H.264 recordings). For the latter, 
VDR sends all pictures and xine replays them at reduced speed for 
slow motion. In case of slow backward, VDR sends only I-frames 
like it does for fast forward or fast backward, but at a much 
slower replay speed.

As for all trickspeed modes which only transfer I-frames, 
vdr-xine inserts a H.264 SequenceEndCode between each frame to 
flush the frame immediately to screen, because the current H.264 
decoder first fills its DPB with 16 frames before it outputs them 
on screen. For all other trickspeed modes (i. e. slow forward) 
you see the delay of filling the DPB.

Regarding your distortions, disable deinterlacing in xine and 
verify, that your distortions go away besides that every second 
line of the image appears in background color. To fix this issue 
please apply a patch to VDR-1.7.17 (which was issued on this 
mailing list) regarding frame detection and rebuild your index file.

Besides that you should also check the following settings in 
.xine/config:

# disable decoder flush at discontinuity
# bool, default: 0
engine.decoder.disable_flush_at_discontinuity:1

# disable decoder flush from video out
# bool, default: 0
engine.decoder.disable_flush_from_video_out:1

Bye.
-- 
Dipl.-Inform. (FH) Reinhard Nissl
mailto:rnissl at gmx.de