[libcamera-devel] [PATCH v3 04/22] libcamera: V4L2VideoDevice: Add tryFormat
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Sat Jul 4 20:15:23 CEST 2020
Hi Paul,
Thank you for the patch.
On Sat, Jul 04, 2020 at 10:31:22PM +0900, Paul Elder wrote:
> Add tryFormat and its variations (meta, single-plane, multi-plane) to
> V4L2VideoDevice.
>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
>
> ---
> New in v3
> ---
> include/libcamera/internal/v4l2_videodevice.h | 4 +
> src/libcamera/v4l2_videodevice.cpp | 121 ++++++++++++++++++
> 2 files changed, 125 insertions(+)
>
> diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h
> index 4d21f5a..56c3aee 100644
> --- a/include/libcamera/internal/v4l2_videodevice.h
> +++ b/include/libcamera/internal/v4l2_videodevice.h
> @@ -186,6 +186,7 @@ public:
> const V4L2Capability &caps() const { return caps_; }
>
> int getFormat(V4L2DeviceFormat *format);
> + int tryFormat(V4L2DeviceFormat *format);
> int setFormat(V4L2DeviceFormat *format);
> std::map<V4L2PixelFormat, std::vector<SizeRange>> formats(uint32_t code = 0);
>
> @@ -217,12 +218,15 @@ protected:
>
> private:
> int getFormatMeta(V4L2DeviceFormat *format);
> + int tryFormatMeta(V4L2DeviceFormat *format);
> int setFormatMeta(V4L2DeviceFormat *format);
>
> int getFormatMultiplane(V4L2DeviceFormat *format);
> + int tryFormatMultiplane(V4L2DeviceFormat *format);
> int setFormatMultiplane(V4L2DeviceFormat *format);
>
> int getFormatSingleplane(V4L2DeviceFormat *format);
> + int tryFormatSingleplane(V4L2DeviceFormat *format);
> int setFormatSingleplane(V4L2DeviceFormat *format);
>
> std::vector<V4L2PixelFormat> enumPixelformats(uint32_t code);
> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
> index 3614b2e..f25914c 100644
> --- a/src/libcamera/v4l2_videodevice.cpp
> +++ b/src/libcamera/v4l2_videodevice.cpp
> @@ -723,6 +723,26 @@ int V4L2VideoDevice::getFormat(V4L2DeviceFormat *format)
> return getFormatSingleplane(format);
> }
>
> +/**
> + * \brief Try an image format on the V4L2 video device
> + * \param[inout] format The image format to test applicablity to the video device
s/applicablity/applicability/
> + *
> + * Test if the supplied \a format to the video device is acceptable, and return
> + * the actually applied format parameters, as \ref V4L2VideoDevice::tryFormat
This is the documentation of V4L2VideoDevice::tryFormat... Did you mean
setFormat() ? You shouldn't need \ref or the V4L2VideoDevice prefix,
writing setFormat() should generate the right link.
Also, the parameters are not "applied". How about
* Try the supplied \a format on the video device without applying it, returning
* the format that would be applied. This is equivalent to setFormat(), except
* that the device configuration is not changed.
> + * would do.
> + *
> + * \return 0 on success or a negative error code otherwise
> + */
> +int V4L2VideoDevice::tryFormat(V4L2DeviceFormat *format)
> +{
> + if (caps_.isMeta())
> + return tryFormatMeta(format);
> + else if (caps_.isMultiplanar())
> + return tryFormatMultiplane(format);
> + else
> + return tryFormatSingleplane(format);
> +}
> +
> /**
> * \brief Configure an image format on the V4L2 video device
> * \param[inout] format The image format to apply to the video device
> @@ -765,6 +785,35 @@ int V4L2VideoDevice::getFormatMeta(V4L2DeviceFormat *format)
> return 0;
> }
>
> +int V4L2VideoDevice::tryFormatMeta(V4L2DeviceFormat *format)
> +{
> + struct v4l2_format v4l2Format = {};
> + struct v4l2_meta_format *pix = &v4l2Format.fmt.meta;
> + int ret;
> +
> + v4l2Format.type = bufferType_;
> + pix->dataformat = format->fourcc;
> + pix->buffersize = format->planes[0].size;
> + ret = ioctl(VIDIOC_TRY_FMT, &v4l2Format);
> + if (ret) {
> + LOG(V4L2, Error) << "Unable to try format: " << strerror(-ret);
> + return ret;
> + }
> +
> + /*
> + * Return to caller the format actually applied on the video device,
> + * which might differ from the requested one.
> + */
> + format->size.width = 0;
> + format->size.height = 0;
> + format->fourcc = V4L2PixelFormat(pix->dataformat);
> + format->planesCount = 1;
> + format->planes[0].bpl = pix->buffersize;
> + format->planes[0].size = pix->buffersize;
> +
> + return 0;
> +}
> +
This is duplicating quite a bit of code. How about turning the existing
setFormatMeta(), setFormatMultiplane() and setFormatSinglePlane()
functions into trySetFormat*(), with a parameter to tell whether to try
the format or set it (can be a "bool set" as these are private
functions, if it was a public API an enum would be better) ?
As the error message is also different (the functions here print "Unable
to try format"), if you want to avoid a (set ? "set" : "try")
conditional, you can move the error messages from the low-level
functions to setFormat() and tryFormat(). Up to you.
With these changes,
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> int V4L2VideoDevice::setFormatMeta(V4L2DeviceFormat *format)
> {
> struct v4l2_format v4l2Format = {};
> @@ -820,6 +869,46 @@ int V4L2VideoDevice::getFormatMultiplane(V4L2DeviceFormat *format)
> return 0;
> }
>
> +int V4L2VideoDevice::tryFormatMultiplane(V4L2DeviceFormat *format)
> +{
> + struct v4l2_format v4l2Format = {};
> + struct v4l2_pix_format_mplane *pix = &v4l2Format.fmt.pix_mp;
> + int ret;
> +
> + v4l2Format.type = bufferType_;
> + pix->width = format->size.width;
> + pix->height = format->size.height;
> + pix->pixelformat = format->fourcc;
> + pix->num_planes = format->planesCount;
> + pix->field = V4L2_FIELD_NONE;
> +
> + for (unsigned int i = 0; i < pix->num_planes; ++i) {
> + pix->plane_fmt[i].bytesperline = format->planes[i].bpl;
> + pix->plane_fmt[i].sizeimage = format->planes[i].size;
> + }
> +
> + ret = ioctl(VIDIOC_TRY_FMT, &v4l2Format);
> + if (ret) {
> + LOG(V4L2, Error) << "Unable to try format: " << strerror(-ret);
> + return ret;
> + }
> +
> + /*
> + * Return to caller the format actually applied on the video device,
> + * which might differ from the requested one.
> + */
> + format->size.width = pix->width;
> + format->size.height = pix->height;
> + format->fourcc = V4L2PixelFormat(pix->pixelformat);
> + format->planesCount = pix->num_planes;
> + for (unsigned int i = 0; i < format->planesCount; ++i) {
> + format->planes[i].bpl = pix->plane_fmt[i].bytesperline;
> + format->planes[i].size = pix->plane_fmt[i].sizeimage;
> + }
> +
> + return 0;
> +}
> +
> int V4L2VideoDevice::setFormatMultiplane(V4L2DeviceFormat *format)
> {
> struct v4l2_format v4l2Format = {};
> @@ -883,6 +972,38 @@ int V4L2VideoDevice::getFormatSingleplane(V4L2DeviceFormat *format)
> return 0;
> }
>
> +int V4L2VideoDevice::tryFormatSingleplane(V4L2DeviceFormat *format)
> +{
> + struct v4l2_format v4l2Format = {};
> + struct v4l2_pix_format *pix = &v4l2Format.fmt.pix;
> + int ret;
> +
> + v4l2Format.type = bufferType_;
> + pix->width = format->size.width;
> + pix->height = format->size.height;
> + pix->pixelformat = format->fourcc;
> + pix->bytesperline = format->planes[0].bpl;
> + pix->field = V4L2_FIELD_NONE;
> + ret = ioctl(VIDIOC_TRY_FMT, &v4l2Format);
> + if (ret) {
> + LOG(V4L2, Error) << "Unable to try format: " << strerror(-ret);
> + return ret;
> + }
> +
> + /*
> + * Return to caller the format actually applied on the device,
> + * which might differ from the requested one.
> + */
> + format->size.width = pix->width;
> + format->size.height = pix->height;
> + format->fourcc = V4L2PixelFormat(pix->pixelformat);
> + format->planesCount = 1;
> + format->planes[0].bpl = pix->bytesperline;
> + format->planes[0].size = pix->sizeimage;
> +
> + return 0;
> +}
> +
> int V4L2VideoDevice::setFormatSingleplane(V4L2DeviceFormat *format)
> {
> struct v4l2_format v4l2Format = {};
--
Regards,
Laurent Pinchart
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