[gst-devel] Reducing the time in GST-registry updating and parsing the command line arguments

[Marco Ballesio]

Hi,

as usual, a late reply. Here anyway my 0.05 €..

On Mon, Nov 22, 2010 at 4:42 PM, tamil arasu <marasu2010 at gmail.com> wrote:
> HI All,
>
>             We are using the gstreamer for  capturing the video .we are
> using packages mentioned below
>
> gst-plugins-good-0.10.14, gst-plugins-base-0.10.23, gstreamer-0.10.23,
> gst-plugins-bad-0.10.13
>
> we are using the pipeline for capturing the video mentioned  below
>
> export GST_REGISTRY_UPDATE=no
> export GST_REGISTRY_FORK=no
>

I don't think it is necessary to set "GST_REGISTRY_FORK=no" in order
to get any improvement. Actually, imo setting this would make things
worse in your case (see below).

> gst-launch rtspsrc location=rtsp://192.168.1.168:8554/mpeg4 latency=100
> name=demux demux. ! queue ! rtpmp4vdepay ! mpeg4videoparse ! dmaidec_mpeg4 !
> TIDmaiVideoSink videoOutput=LCD videoStd=320X240 demux. ! queue !
> rtppcmudepay ! mulawdec ! alsasink
>
> When we launch the above mentiond pileline on the command line,we are able
> to display video on Lcd.The output is
>
> Setting pipeline to PAUSED ...
> Pipeline is live and does not need PREROLL ...
> Setting pipeline to PLAYING ...
> DavinciDisplay DavinciDisplay.1: Before finishing with S_FMT:
> layer.pix_fmt.bytesperline = 320,
>  layer.pix_fmt.width = 320,
>  layer.pix_fmt.height = 240,
>  layer.pix_fmt.sizeimage =115200
> New clock: GstSyDavinciDisplay DavinciDisplay.1: pixfmt->width = 320,
>  layer->layer_info.config.line_length= 320
> stemClock
>
> Once I run the above command ,its taking 2 second to get  the  first message
> (Setting pipeline to PAUSED ...).
> one second for update the registry,

it's strange, as you've set GST_REGISTRY_UPDATE to "no". How did you
understand this latency is caused when updating the registry?

In gstregistry.c, setting GST_REGISTRY_FORK=no forces the scan helper
state to "REGISTRY_SCAN_HELPER_NOT_STARTED" in opposition to
"REGISTRY_SCAN_HELPER_DISABLED".

Just to say that, probably, disabling forks you did preempts any
settings in GST_REGISTRY_UPDATE and triggers a registry generation
anyway.

> anothe one second for parsing the command
> line arguments.(gst_parse_launchv)
>

you'll get rid of this by building the pipeline "manually" in a custom
application. See here for more help:

http://www.gstreamer.net/data/doc/gstreamer/head/manual/html/index.html

> how to reduce the this 2 second.Can anyone help me on this issue?

See above. Probably some extra-latency is caused by the video decoder
buffering a fixed amount of memory but, as long as your source is in
the local filesystem, its effect would be negligible.

Regards

>
>
> thanks and regards,
>
> Arasu.M
>
>
>
>
>
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