Why ist v4l2grab using a 4 stage buffer (req.count = 4) if it actually just writes one

This is from the code example (<a href="http://linuxtv.org/downloads/v4l-dvb-apis/capt

Buffer size larger than required about v4l2grab HOT 2 CLOSED

twam commented on September 4, 2024

Buffer size larger than required

from v4l2grab.

Comments (2)

twam commented on September 4, 2024

This is from the code example (http://linuxtv.org/downloads/v4l-dvb-apis/capture-example.html). The documention of ioctl VIDIOC_REQBUFS (http://linuxtv.org/downloads/v4l-dvb-apis/vidioc-reqbufs.html) says 'A larger number is also possible when the driver requires more buffers to function correctly', but I haven't found out so far which function need what number of buffers.

I'll have a look into it as soon as I have some spare time :)

from v4l2grab.

mrflow commented on September 4, 2024

So this is a legitimate overhead for working on as many devices as possible.

For me it was possible to reduce it to 1 without side-effects (with uvcvideo - otherwise I had 5 pictures delay in my video transmission).
(I am working on a RC-Car with video transmission: fubar.ath.cx/upstream/wiki)

from v4l2grab.

Recommend Projects