On 01/12/2015 04:35 PM, Philipp Zabel wrote:
> Hi Hans,
>
> thank you for the comments!
>
> Am Montag, den 12.01.2015, 16:03 +0100 schrieb Hans Verkuil:
>> On 12/22/2014 05:00 PM, Philipp Zabel wrote:
>>> The encoder needs to know the nominal framerate for the constant bitrate
>>> control mechanism to work. Currently the only way to set the framerate is
>>> by using VIDIOC_S_PARM on the output queue.
>>>
>>> Signed-off-by: Philipp Zabel <p.za...@pengutronix.de>
>>> ---
>>> drivers/media/platform/coda/coda-common.c | 29
>>> +++++++++++++++++++++++++++++
>>> 1 file changed, 29 insertions(+)
>>>
>>> diff --git a/drivers/media/platform/coda/coda-common.c
>>> b/drivers/media/platform/coda/coda-common.c
>>> index 39330a7..63eb510 100644
>>> --- a/drivers/media/platform/coda/coda-common.c
>>> +++ b/drivers/media/platform/coda/coda-common.c
>>> @@ -803,6 +803,32 @@ static int coda_decoder_cmd(struct file *file, void
>>> *fh,
>>> return 0;
>>> }
>>>
>>> +static int coda_g_parm(struct file *file, void *fh, struct v4l2_streamparm
>>> *a)
>>> +{
>>> + struct coda_ctx *ctx = fh_to_ctx(fh);
>>> +
>>
>> If a->type != V4L2_BUF_TYPE_VIDEO_OUTPUT, then return -EINVAL.
>
> If the decoder can retrieve the framerate from the stream, wouldn't it
> make sense to allow G_PARM for a->type == V4L2_BUF_TYPE_VIDEO_CAPTURE ?
Certainly. But that wasn't in the patch :-)
Regards,
Hans
>
>> Ditto for s_parm.
>
> Will do.
>
>>> + a->parm.output.timeperframe.denominator = 1;
>>> + a->parm.output.timeperframe.numerator = ctx->params.framerate;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int coda_s_parm(struct file *file, void *fh, struct v4l2_streamparm
>>> *a)
>>> +{
>>> + struct coda_ctx *ctx = fh_to_ctx(fh);
>>> +
>>> + if (a->type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
>>> + a->parm.output.timeperframe.numerator != 0) {
>>> + ctx->params.framerate = a->parm.output.timeperframe.denominator
>>> + / a->parm.output.timeperframe.numerator;
>>
>> Hmm, what happens if the denominator is 1 and the numerator is 2?
>> You probably want to clamp ctx->params.framerate to the range of allowed
>> framerates.
>> And at least ensure a framerate > 0.
>>
>> Also check with v4l2_compliance! You'd have caught at least the missing
>> a->type check.
>
> Oh dear, I need to improve my v4l-utils update habits. I'll fix this
> patch and resend it.
>
> regards
> Philipp
>
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