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    SubjectRe: [PATCH v5 00/39] i.MX Media Driver
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    On 03/18/2017 12:22 PM, Russell King - ARM Linux wrote:
    > Hi Steve,
    >
    > I've just been trying to get gstreamer to capture and h264 encode
    > video from my camera at various frame rates, and what I've discovered
    > does not look good.
    >
    > 1) when setting frame rates, media-ctl _always_ calls
    > VIDIOC_SUBDEV_S_FRAME_INTERVAL with pad=0.
    >
    > 2) media-ctl never retrieves the frame interval information, so there's
    > no way to read it back with standard tools, and no indication that
    > this is going on...

    I think Philipp Zabel submitted a patch which addresses these
    in media-ctl. Check with him.

    >
    > 3) gstreamer v4l2src is getting upset, because it can't enumerate the
    > frame sizes (VIDIOC_ENUM_FRAMESIZES fails),

    Right, imx-media-capture.c (the "standard" v4l2 user interface module)
    is not implementing VIDIOC_ENUM_FRAMESIZES. It should, but it can only
    return the single frame size that the pipeline has configured (the mbus
    format of the attached source pad).

    > which causes it to
    > fallback to using the "tvnorms" to decide about frame rates. This
    > makes it impossible to use frame rates higher than 30000/1001, and
    > causes the pipeline validation to fail.

    In v5 I added validation of frame intervals between pads,
    but due to negative feedback I've pulled that. So next
    version will not attempt to validate frame intervals between
    source->sink pads.

    Can you share your gstreamer pipeline? For now, until
    VIDIOC_ENUM_FRAMESIZES is implemented, try a pipeline that
    does not attempt to specify a frame rate. I use the attached
    script for testing, which works for me.



    >
    > 0:00:01.937465845 20954 0x15ffe90 DEBUG v4l2 gstv4l2object.c:2474:gst_v4l2_object_probe_caps_for_format:<v4l2src0> Enumerating frame sizes for RGGB
    > 0:00:01.937588518 20954 0x15ffe90 DEBUG v4l2 gstv4l2object.c:2601:gst_v4l2_object_probe_caps_for_format:<v4l2src0> Failed to enumerate frame sizes for pixelformat RGGB (Inappropriate ioctl for device)
    > 0:00:01.937879535 20954 0x15ffe90 LOG v4l2 gstv4l2object.c:2708:gst_v4l2_object_get_nearest_size:<v4l2src0> getting nearest size to 1x1 with format RGGB
    > 0:00:01.937990874 20954 0x15ffe90 LOG v4l2 gstv4l2object.c:2724:gst_v4l2_object_get_nearest_size:<v4l2src0> got nearest size 816x616
    > 0:00:01.938250889 20954 0x15ffe90 ERROR v4l2 gstv4l2object.c:1873:gst_v4l2_object_get_interlace_mode: Driver bug detected - check driver with v4l2-compliance from http://git.linuxtv.org/v4l-utils.git
    > 0:00:01.938326893 20954 0x15ffe90 LOG v4l2 gstv4l2object.c:2708:gst_v4l2_object_get_nearest_size:<v4l2src0> getting nearest size to 32768x32768 with format RGGB
    > 0:00:01.938431566 20954 0x15ffe90 LOG v4l2 gstv4l2object.c:2724:gst_v4l2_object_get_nearest_size:<v4l2src0> got nearest size 816x616
    > 0:00:01.939776641 20954 0x15ffe90 ERROR v4l2 gstv4l2object.c:1873:gst_v4l2_object_get_interlace_mode: Driver bug detected - check driver with v4l2-compliance from http://git.linuxtv.org/v4l-utils.git
    > 0:00:01.940110660 20954 0x15ffe90 DEBUG v4l2 gstv4l2object.c:1955:gst_v4l2_object_get_colorspace: Unknown enum v4l2_colorspace 0
    >
    > This triggers the "/* Since we can't get framerate directly, try to
    > use the current norm */" code in v4l2object.c, which causes it to
    > select one of the 30000/1001 norms:
    >
    > 0:00:01.955927879 20954 0x15ffe90 INFO v4l2 gstv4l2object.c:3811:gst_v4l2_object_get_caps:<v4l2src0> probed caps: video/x-bayer, format=(string)rggb, framerate=(fraction)30000/1001, width=(int)816, height=(int)616, pixel-aspect-ratio=(fraction)1/1; video/x-raw, format=(string)I420, framerate=(fraction)30000/1001, width=(int)816, height=(int)616, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1; video/x-raw, format=(string)YV12, framerate=(fraction)30000/1001, width=(int)816, height=(int)616, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1; video/x-raw, format=(string)BGR, framerate=(fraction)30000/1001, width=(int)816, height=(int)616, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1; video/x-raw, format=(string)RGB, framerate=(fraction)30000/1001, width=(int)816, height=(int)616, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1
    >
    > despite the media pipeline actually being configured for 60fps.
    >
    > Forcing it by adjusting the pipeline only results in gstreamer
    > failing, because it believes that v4l2 is unable to operate at
    > 60fps.
    >
    > Also note the complaints from v4l2src about the non-compliance...

    Thanks, I've fixed most of v4l2-compliance issues, but this is not
    done yet. Is that something you can help with?

    Steve

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