Dear Lian,<br>
<br>
Thanks It's a great initiative.<br>
<br>
If we need to understand userspace and kernel interaction then I
believer <a href="https://github.com/amery/allwinner-a10-video">https://github.com/amery/allwinner-a10-video</a> will be a batter
start.<br>
<br>
Here they have very well documented Video playback process which very thin library.<br>
<br>
I believe this will be much faster we first make it working and the trace other libs there.<br>
<br>
CedarXPlayerTest is a huge program with lots of other feature like Contener format parsing Codec Call Audio Video syncing.<br>
<br>
<br>
How ever if the objective is to make full functional player then we have two option.<br>
<br>
One the way your are going.<br>
<br>
Other we use a10-video + ffmpeg + FFPlay (with Pathch).<br>
<br>
Where code will be more crystal clear.<br><br><div class="gmail_quote">On Tue, Aug 14, 2012 at 3:14 AM, Iain Bullard <span dir="ltr"><<a href="mailto:iain.bullard@gmail.com" target="_blank">iain.bullard@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi All,<br>
<br>
Recently I've been working on understanding how the CedarX decoder<br>
chip works in order to write an open source library for running the<br>
video decoder chip found in Allwinner A10 devices.<br>
<br>
To do this I've written a library which is effectively libsegfault<br>
from the DRI reverse engineering project<br>
(<a href="http://dri.freedesktop.org/wiki/ReverseEngineering" target="_blank">http://dri.freedesktop.org/wiki/ReverseEngineering</a>) for arm devices,<br>
which could be used in other projects to understand how user land<br>
drivers operate (or actually, anything which is reading and writing to<br>
mmaped memory). The memory tracing is generic and not specific to<br>
Allwinner devices or the CedarX decoder chip.<br>
<br>
Just to be super clear: this is not an open decoder for Allwinner A10<br>
devices just a step towards one.<br>
<br>
My next step is to start analysing the data from the tracing library<br>
and see where it takes me.<br>
<br>
More information and the source code to the tracing library can be found here:<br>
<a href="https://github.com/iainb/CedarXWrapper" target="_blank">https://github.com/iainb/CedarXWrapper</a><br>
<br>
A sample player (taken from the original Mele Ubuntu image) can be found here:<br>
<a href="https://github.com/iainb/CedarXPlayerTest" target="_blank">https://github.com/iainb/CedarXPlayerTest</a><br>
<br>
And sample output from tracing can be found here:<br>
<a href="https://github.com/iainb/CedarXWrapper/downloads" target="_blank">https://github.com/iainb/CedarXWrapper/downloads</a><br>
<br>
Iain.<br>
<br>
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</blockquote></div><br><br clear="all"><br>-- <br>Thanks & Regards<br><br>Piyush Verma<br><br><br>