Linux: [DRA746]Could libdce follow common codec interface？

Halley Zhao

Tool/software: Linux

libdce has well defined API/data-structures, however, it is still a new thing to me.

I think it will be better if libdce follows international standard interface, for example: use the command and structure defined by Linux V4L2: https://github.com/01org/libyami/blob/master/v4l2/v4l2codec_device_ops.h

in short, it uses the semantic/data-structure of v4l2 to describe codec interface; w/o anything of hardware platform special.

yes, additional wrapper seems not value much; but it helps new comes to use libdce much easier. potentially ease the adoption of TI silicon.

over 8 years ago

0 Pavel Botev over 8 years ago

TI__Guru**** 170625 points

Hi Halley,

Refer to the below links for more info regarding libdce:

processors.wiki.ti.com/.../Processor_Training:_Multimedia
processors.wiki.ti.com/.../Processor_SDK_Linux_Automotive_Data_Sheet

github.com/.../libdce

Regards,
Pavel

0 Halley Zhao over 8 years ago in reply to Pavel Botev

Intellectual 560 points

[ignore it, this reply doesn't match this thread. but another one submitted by me]

thanks,

I had read the wiki before. they doesn't address my questions.

for the source code at github, it doesn't help my questions either. it is too old ( the latest update happened 5 years ago)

0 Pavel Botev over 8 years ago in reply to Halley Zhao

TI__Guru**** 170625 points

What are your questions?

libdce that comes with DRA7x PSDKLA 3.02 is: libdce1 3.00.12.00-r4.0, taken from:

This source code is 2 weeks old

0 Ramprasad over 8 years ago in reply to Pavel Botev

TI__Mastermind 30480 points

Hi Halley,
libdce is a userspace library to invoke audio and video codes for encoding and decoding like mp3, aac, h264, mpeg4 etc running on DSP and IVAHD with TI's XDM APIs.
Here codec refers to these type of formats.

0 Halley Zhao over 8 years ago in reply to Ramprasad

Intellectual 560 points

yes, I know that libdce is codec lib.

if you look at github.com/.../V4L2-Codec and github.com/.../v4l2codec_device_ops.h
you will know that I'm talking about video codec as well. (not camera).

the idea borrows the data structure and command semantic of linux v4l2 to define codec interface.

0 Buddy L. over 8 years ago in reply to Halley Zhao

TI__Intellectual 2540 points

Hi Halley,
Off course libdce can be modified to follow linux common codec interface like v4l2 but TI is not planning to invest in it.
Since libdce is opened to public, it is up to community to utilize it or modify it to fit customer needs.
On TI products, libdce is used commonly for Android, Linux, and QNX HLOS.
One of the main reason we don't use v4l2 on libdce is because libdce is also used by QNX HLOS, and their MMF is not interfacing with v4l2.

Btw, a little correction on Ramprasad comment, libdce is a userspace to TI video codec library for encoding and decoding. No audio encoding or decoding takes place in libdce.

Thanks.
//Buddy

0 Halley Zhao over 8 years ago in reply to Buddy L.

Intellectual 560 points

thanks, I got your points.

by the way, v4l2 interface can be used on QNX HLOS as well. since only 2 header files are used (like omx header), not introduce any run time dependency.

0 Buddy L. over 8 years ago in reply to Halley Zhao

TI__Intellectual 2540 points

Hi Halley,

Yes, I think QNX HLOS can use V4L2 interface as well, but the V4L2 codec driver interface needs to be made available to public because V4L2 is licensed under GNU General Public License. LIBDCE was originally used by QNX HLOS only and the component was not made for public. Only after LIBDCE is getting used by Linux and Android HLOS, the source code is made public.

And since TI products that uses LIBDCE are stable, mature and reliable, there is no point in changing or introducing V4L2 interface for LIBDCE which could potentially introduced issues. Like I stated previously, since LIBDCE has been made public, we welcome any contributions in adding V4L2 interface for LIBDCE.

Thanks.
//Buddy

0 Halley Zhao over 8 years ago in reply to Buddy L.

Intellectual 560 points

thanks， I may consider it in the future.

in short term, i'd make sure libdce runs correct in my media framework.

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Linux: [DRA746]Could libdce follow common codec interface？