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why frameformat instead pixelformat?

DISCUSSION Tom 2 participants 3 messages Mar 24, 2014 – Mar 26, 2014 Media (V4L/DVB)

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Tom

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Hello,

while reading into the media-api issue I found out that for configuring the entity pads a frameformat is used.

For that I found the negotiation rfc of that topic, but I don't really get the relevance of a frameformat.

http://www.spinics.net/lists/linux-media/msg10006.html

Can anyone explain why the media-api uses the frameformat instead of the pixelformat and what the main differences are?

Thanks in advance.

Best regards,
Tom

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#1 lore raw
Quoted 7 lines · Tom <Bassai_Dai <at> gmx.net> writes:

Hello,

...
For that I found the negotiation rfc of that topic, but I don't really get the relevance of a frameformat.

Quoted 5 lines

http://www.spinics.net/lists/linux-media/msg10006.html

Can anyone explain why the media-api uses the frameformat instead of the pixelformat and what the main differences are?
...

Can really nobody explain me why the media-api uses the v4l2_mbus_framefmt instead of the v4l2_format??

#2 lore raw
In reply to Tom
Quoted 5 lines · Tom

Hello,

while reading into the media-api issue I found out that for configuring the entity pads a frameformat is used.

Quoted 7 lines

For that I found the negotiation rfc of that topic, but I don't really get the relevance of a frameformat.

http://www.spinics.net/lists/linux-media/msg10006.html

Can anyone explain why the media-api uses the frameformat instead of the pixelformat and what the main differences are?

The pixelformat describes the image format in memory, the mbus_framefmt describes the image data as it is transferred over a hardware bus.

It's as simple as that. While the two are related (i.e. to get a certain pixelformat you probably need to set up a specific mbus_framefmt), the details of this relationship are board or even use-case dependent.

Regards,

Hans