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Bug 641191 - dvbsrc: add a property to configure the dvb-api buffer size
dvbsrc: add a property to configure the dvb-api buffer size
Status: RESOLVED FIXED
Product: GStreamer
Classification: Platform
Component: gst-plugins-bad
git master
Other All
: Normal enhancement
: 1.0.0
Assigned To: GStreamer Maintainers
GStreamer Maintainers
Depends on:
Blocks:
 
 
Reported: 2011-02-01 21:48 UTC by Fabrizio Milo
Modified: 2014-06-22 13:15 UTC
See Also:
GNOME target: ---
GNOME version: ---


Attachments
Patch + gst-indent adjustments (6.38 KB, patch)
2011-02-01 21:48 UTC, Fabrizio Milo
committed Details | Review

Description Fabrizio Milo 2011-02-01 21:48:09 UTC
Created attachment 179837 [details] [review]
Patch + gst-indent adjustments

The DVB-api is able to specify the size of the kernel-buffer for the dvr device.
This can be useful for tuning.

See http://www.linuxtv.org/docs/dvbapi/DVB_Demux_Device.html#SECTION00429000000000000000
Comment 1 Tim-Philipp Müller 2011-03-14 21:06:06 UTC
Could you elaborate a bit on how/why this is useful exactly? 

You're drastically reducing the DMX_BUFFER_SIZE from 1MB to 8kB here if I read this correct - won't that be problematic if read()s aren't done fast enough, e.g. because downstream blocks for a short while, as often happens? (I see that 8kB is also the default buffer size, just wondering...)

May I suggest that the property be a normal signed int, defaulting to -1, in which case dvbsrc just uses whatever defaults it deems best? Why not just call it "buffer-size"?

Some more nitpicks:

 - instead of logging errno, please log g_strerror(errno).

 - in property description, mention that the size is in bytes

 - please don't indent header files, only .c files should be
   indented.
Comment 2 Fabrizio Milo 2011-04-14 21:45:42 UTC
This patch contains a wrong PRE-DEFINED buffer size.
I think being able to specify a dvb parameter should be part of our interface and it allows to fine tune your hardware.

You can see all my work on this element at:

https://github.com/Mistobaan/gst-plugins-bad/commits/dvbsrc_poll_tuning
Comment 3 Fabrizio Milo 2011-04-14 22:02:06 UTC
dvb-buffer-size is better than buffer-size to avoid confusion ( dvb-buffer-size is the one inside the kernel
Comment 4 Edward Hervey 2012-06-18 15:53:20 UTC
I agree being able to configure the kernel-buffer-size is a good idea.

What needs to be fixed is the default value though.

Can you rebase this on current 0.10 ?
Comment 5 Tobias Mueller 2012-10-29 18:22:23 UTC
Setting to NEW as this seems to be an issue that needs to be fixed as per comment #4.

Fabrizio, can you rebase your patch, please? Thanks in advance!
Comment 6 Reynaldo H. Verdejo Pinochet 2014-05-01 22:46:33 UTC
Comment on attachment 179837 [details] [review]
Patch + gst-indent adjustments

default buffer size adjusted.
Comment 7 Reynaldo H. Verdejo Pinochet 2014-05-01 22:46:57 UTC
This enhancement was committed as fe5cf525e1de8320d1db67914
with the default buffer size to (10*188*1024). Closing.