[linux-dvb] [RFC] ioctls to read PTS of a decoder

Andreas Oberritter obi at linuxtv.org
Thu Feb 16 16:59:54 CET 2006


On Thu, 2006-02-16 at 18:46 +0400, Manu Abraham wrote:
> I thought you wanted to parse the stream and provide the PTS/DTS for 
> decoders. Be it Hardware or Software, the decoder works in the same way, 
> both use PTS/DTS info. in the case of hardware, this is done in 
> hardware, but i do understand that you would like to parse this ahead so 
> you can use that info for stream control.

Wrong. The stream is parsed, decoded and displayed by the hardware.
There is no software parsing involved. The PTS value can be read through
a register of the decoder. Think Set-Top-Box not PC.

> Even software decoders make use of PTS/DTS parsing from the stream, so 
> if it is anyway parsed, then it would make little sense as to parse the 
> stream again, whether be it in userspace for a decoder (Software based). 
> Software decoders will required to be modified to take advantage of this.

To repeat myself: Software decoders are used for cards without hardware
decoders. Those cards do not have audio or video API devices, i.e. don't
use linux/dvb/{audio,video}.h.

> So do you mean to say that the in kernel parsing should be done only for 
> Hardware decoders .. ?

There is no in-kernel parsing. There is also no common dvb-core code for
audio and video devices. Those devices are always implemented by
hardware drivers.

Best regards,
Andreas




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