Re: Demande de support V4L2

Re: Demande de support V4L2

[Laurent Pinchart]

Hi Loïc,

As you've CC'ed the linux-media mailing list, I'll answer in English.

On Thursday 03 March 2011 18:25:29 Loïc Akue wrote:
> Bonjour Laurent,
> 
> J'ai un peu avancé dans ma tentative de mise en place de la capture vidéo.
> J'ai réussi à lever mon problème d'erreur de segmentation au démarrage, qui
> était due à une incompatibilité entre mon driver "saa7115.c" et celui de
> l'omap3isp.
> 
> Cette étape passée, j'ai entrepris d'utiliser 'media-ctl' pour configurer
> mes entités, et 'yavta' pour capturer de l'image.
> 
> Après avoir bloqué pendant quelque jours, je voulais savoir si l'entité
> CCDC acceptait que j'essaie de lui envoyer de la vidéo au format UYVY (
> V4L2_MBUS_FMT_UYVY8_1X16 ou V4L2_MBUS_FMT_Y8_1X8 ) ?
> 
> Désolé pour mes questions de débutant, mais je voudrais comprendre mes
> erreurs pour être sur d'aller dans la bonne direction.

The OMAP3 ISP CCDC module doesn't support V4L2_MBUS_FMT_UYVY8_1X16 yet. It 
should support V4L2_MBUS_FMT_Y8_1X8, but inteprets it as raw bayer data, so 
you will get strange results from the preview engine RGB to YUV conversion 
filter. You should be able to capture V4L2_MBUS_FMT_Y8_1X8 data at the CCDC 
output though. Feeding YUV data directly from the CCDC to the resizer, which 
is supported by the driver, isn't implemented yet.

-- 
Regards,

Laurent Pinchart

Re: Demande de support V4L2

[Laurent Pinchart]

Hi Loïc,

On Thursday 03 March 2011 18:51:21 Loïc Akue wrote:
> Thanks you for the reply,
> 
> I already tried to contact the mailing list, but I didn't get the help
> expected =s I get I just be patient, and keep on trying.
> 
> So, according to your answer, the CCDC should be able to provide some YUV
> data, that I can get on the /dev/video2 node, using the yavta application.
> Correct me if I'm wrong.

The CCDC is able to handle both YUV and raw Bayer data. YUV data can be saved 
to memory through the CCDC output video node or forwarded to the resizer. Raw 
Bayer data can be saved to memory or forwarded to the preview engine.

YUV support for the CCDC module is not implemented yet in the ISP driver. The 
CCDC to resizer link hasn't been tested.

8-bit grey data is supported by the ISP driver. It's currently considered by 
the CCDC as raw Bayer data. As the CCDC doesn't perform Bayer to YUV 
conversion, you can save 8-bit grey data to memory at the CCDC output. 
Forwarding 8-bit grey data to the preview engine will work but will produce 
weird results as the preview engine will process it as raw Bayer data.

-- 
Regards,

Laurent Pinchart

Re: Demande de support V4L2

[Laurent Pinchart]

Hi Loïc,

On Thursday 10 March 2011 18:07:52 Loïc Akue wrote:
> Hi Linux, Media.
> 
> I'd like you to help me understand how the yavta application uses the
> omap3isp interrupts to capture some frames please.

Applications don't "use" the OMAP3 ISP interrupts. They interface with the 
driver through the MC and V4L2 APIs. The OMAP3 ISP driver handles the 
interrupts internally.

> When I use the yavta application to capture raw data from the CCDC output,
> the system hangs. I reduced the numbers of lines to reach, to generate the
> VD0 interrupt, but I still can get any images.

-- 
Regards,

Laurent Pinchart

Re: Demande de support V4L2

[Laurent Pinchart]

Hi Loïc,

On Friday 18 March 2011 16:43:40 Loïc Akue wrote:
> Hi,
> 
> Do you know if Gstreamer or Mplayer are able to capture some vidéo from the
> CCDC output?
> I've been trying with the v4l2src plugin but Gstreamer "can negociate
> format".

I haven't tried mplayer or v4l2src with the OAMP3 ISP, sorry.

-- 
Regards,

Laurent Pinchart

Re: Demande de support V4L2

[Michael Jones]

On 03/21/2011 06:43 PM, Laurent Pinchart wrote:
> Hi Loïc,
> 
> On Friday 18 March 2011 16:43:40 Loïc Akue wrote:
>> Hi,
>>
>> Do you know if Gstreamer or Mplayer are able to capture some vidéo from the
>> CCDC output?
>> I've been trying with the v4l2src plugin but Gstreamer "can negociate
>> format".
> 
> I haven't tried mplayer or v4l2src with the OAMP3 ISP, sorry.
> 


Hi Loïc,

GStreamer relies on ENUM_FMT to negotiate the format, which the current
ISP driver doesn't provide.  I have patched my kernel to do this and I
have gotten GStreamer to display UYVY images from the previewer output,
but I haven't spent much time trying to get it from the CCDC yet.  I
would be interested to hear your progress there.

I will submit my ENUM_FMT patch to the list in a different thread.

-Michael

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