Re: [PATCH] libv4lconvert: clarify the behavior and resulting restrictions of v4lconvert_convert()

[Hans de Goede <hdegoede@redhat.com>]

Hi Frank,

Thanks for all your work on this. I'm afraid that atm I'm very busy
with work, so I don't have time to review your patches. I hope to
find some time for this next weekend...

Regards,

Hans


On 10/03/2012 06:48 PM, Frank Schäfer wrote:
> Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
> ---
>   lib/include/libv4lconvert.h |   20 ++++++++++++++++++--
>   1 Datei geändert, 18 Zeilen hinzugefügt(+), 2 Zeilen entfernt(-)
>
> diff --git a/lib/include/libv4lconvert.h b/lib/include/libv4lconvert.h
> index 167b57d..509655e 100644
> --- a/lib/include/libv4lconvert.h
> +++ b/lib/include/libv4lconvert.h
> @@ -89,8 +89,24 @@ LIBV4L_PUBLIC int v4lconvert_needs_conversion(struct v4lconvert_data *data,
>   		const struct v4l2_format *src_fmt,   /* in */
>   		const struct v4l2_format *dest_fmt); /* in */
>
> -/* return value of -1 on error, otherwise the amount of bytes written to
> -   dest */
> +/* This function does the following conversions:
> +    - format conversion
> +    - cropping
> +   if enabled:
> +    - processing (auto whitebalance, auto gain, gamma correction)
> +    - horizontal/vertical flipping
> +    - 90 degree (clockwise) rotation
> +
> +   NOTE: the last 3 steps are enabled/disabled depending on
> +    - the internal device list
> +    - the state of the (software emulated) image controls
> +
> +   Therefore this function should
> +    - not be used when getting the frames from libv4l
> +    - be called only once per frame
> +   Otherwise this may result in unintended double conversions !
> +
> +   Returns the amount of bytes written to dest an -1 on error */
>   LIBV4L_PUBLIC int v4lconvert_convert(struct v4lconvert_data *data,
>   		const struct v4l2_format *src_fmt,  /* in */
>   		const struct v4l2_format *dest_fmt, /* in */
>