H264 hardware encoding examples

VIM3
1

Hi @numbqq, @Frank!

I’ve got some questions about hardware video encoding.

So I need to encode input video (MIPI Khadas cam), using only gstreamer it works (really works!) like:

gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw,width=1920,height=1080,framerate=60/1,format=RGB ! videoconvert  ! x264enc ! filesink location=/tmp/test.avi

But now the question: How can I use hardware accelerated encoding? Like things described there, for example. Two years ago you wrote such a pipeline:

gst-launch-1.0 v4l2src device=/dev/video0  ! amlvdec ! amlvsink sync=false

Its output (errors) looks like:

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Internal data stream error.
Additional debug info:
gstbasesrc.c(3072): gst_base_src_loop (): /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
streaming stopped, reason not-negotiated (-4)
Execution ended after 0:00:00.001708664
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
Freeing pipeline ...

If I use it like I wrote above (standart gstreamer pipeline):

gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw,width=1920,height=1080,framerate=60/1,format=RGB ! videoconvert  ! amlvdec ! amlvsink sync=false ! filesink location=/tmp/test.avi

I get warnings and nothing good like:

WARNING: erroneous pipeline: could not link videoconvert0 to amlvdec0

or

WARNING: erroneous pipeline: could not link v4l2src0 to amlvdec0, amlvdec0 can't handle caps video/x-raw, width=(int)1920, height=(int)1080, framerate=(fraction)60/1, format=(string)RGB

And can you please tell, what hardware is used by gstreamer (above) to encode?

Best regards,
Maxim

2

Hardware encoding with gstreamer may not work well, please use the hardware encoder library.

3

@numbqq

I tried to use that library for raw *.rgb video file and it works well. But it’s not exactly what I am looking for.

Could you please provide some examples/thoughts, how can I use that library for MIPI camera stream encoding?

Best regards,
Maxim

4

You can grab raw rgb frames from MIPI camera and feed to encoder library.

5

@numbqq @Frank
Also I should save frames to device, and than encode them?
I think that will take too much time.

Or how can I grab frames directly?

h264EncoderDemo 'v4l2src device=/dev/video0' /tmp/encoded.mp4 1920 1080 10 30 8000000 200 3

raises an error:

v4l2src device=/dev/video0
/tmp/encoded.mp4
src_url is: v4l2src device=/dev/video0 ;
out_url is: /tmp/encoded.mp4 ;
width   is: 1920 ;
height  is: 1080 ;
gop     is: 10 ;
frmrate is: 30 ;
bitrate is: 8000000 ;
frm_num is: 200 ;
open src file error!

Best regards,
Maxim

6

The MIPI camera use the standard V4L2 driver, so you can use V4L2 api to grab the frames, here is an example.

https://docs.khadas.com/linux/vim3/MIPICamera.html#Use-MIPI-Camera-via-opencv

1 Like
7

Hello,

No plans to permit hardware encoding with a kernel mainline ?
Regards,

8

@numbqq @Frank

Could you please provide an exact example?
I can’t grab frames using v4l2 driver - it raises errors.

Best regards,
Maxim