[linux-dvb] hvr 1300 mpeg sound / video issues + patches

Frederic CAND frederic.cand at anevia.com
Wed Sep 17 12:27:15 CEST 2008

Dear all,

I'm experiencing an issue I had experienced previously which I though I 
got rid of but in fact no.
The issue is :

I tune the card through the [v4l] device (open/ioctls/close), then read 
the mpeg PS through the [mpeg] device. This is working.
But closing the mpeg device, retuning the [v4l] device 
(open/ioctls/close) the reopening for read the [mpeg] device will yield 
in raspy sound and/or blinking black banner on the top of the video 
frames ...

I'm using a kernel
I'm using a quite fresh v4l-dvb snapshot (rev e5ca4534b543 of September 
9th, changeset 8963)
I'm using v4l-cx2341x-enc.fw which md5sum is 
9b39b3d3bba1ce2da40f82ef0c50ef48 from 

By the way the mpeg was not providing anything (i.e only I/O errors) 
when selecting the analog tv tuner input so I took some time looking for 
a snapshot with tuner working and I came up with the attached 
hvr-1300-tuner-fix.patch patch file.
I don't get why but this is simply a diff between rev b7bb2b116cbb 
(changeset 7442) and its child rev 13244661a8df (changset 7483) and it 
worked for me (7442 had tuner working, 7483 had not). Applying this 
patch on recent snapshots make the analog tuner work for me ... so if 
anyone can check if it's ok or if I missed an important point ...

Another thing : the way I work with the [mpeg] device was polling the 
device, then read from it if any data is available. But the [mpeg] is 
not providing anything until a read call has initiated the codec (i.e a 
call to blackbird_start_codec). So I came up with the attached 
cx88-blackbird-poll-fix.patch patch file.
Thus, anyone willing to have a generic implementation of timeout polling 
before trying to read the device would be glad to be able to.

So if anyone has an understanding of my first issue (raspy sound / 
blinkg black banner on top of the video after some retuning function 
calls), can reproduce it, and / or has an idea on how to fix this, help 
would be greatly appreciated !


CAND Frederic
Product Manager
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: hvr-1300-tuner-fix.patch
Url: http://www.linuxtv.org/pipermail/linux-dvb/attachments/20080917/a98c0f4d/attachment.txt 
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: cx88-blackbird-poll-fix.patch
Url: http://www.linuxtv.org/pipermail/linux-dvb/attachments/20080917/a98c0f4d/attachment-0001.txt 

More information about the linux-dvb mailing list