prevent color conversion for shm src/sink

[Erik Rull]

Hi Josh,

sorry - one item is wrong on my side, but if I "correct" it, I don't see
anything at all on the ximagesink!
It's already some time ago, I wrote this part of code for appsrc, that's why I
did not remember all bits and pieces ;-)

So my corrected pipeline now actually dumps out 8 bit items in appsrc (also
internally in the appsrc implementation!):

aravissrc camera-name=172.17.48.35 num-buffers=10 exposure=100000 gain-auto=0 !
video/x-raw,format=GRAY8,width=640,height=512,framerate=8/1 ! videoconvert  !
videobalance contrast=1.4 brightness=-0.3 contrast=1.8  ! videoconvert  !
video/x-raw,format=GRAY8 ! appsink name=sink max-buffers=10 drop=1
(same as before)

appsrc name=src stream-type=0 is-live=1 max-bytes=10000000
caps=video/x-raw,format=(string)GRAY8,framerate=8/1,width=401,height=404 !
shmsink render-delay=0 socket-path=/tmp/pad_shm shm-size=10000000
wait-for-connection=0 max-lateness=500000000 buffer-time=0
(internally corrected to real GRAY8 bit)

shmsrc socket-path=/tmp/pad_shm is-live=1 !
video/x-raw,format=(string)GRAY8,framerate=(fraction)8/1,pixel-aspect-ratio=(fraction)1/1,interlace-mode=(string)progressive,width=401,height=404
! videoconvert  ! identity name=identity ! ximagesink max-lateness=500000000
name=sink
(adapted to GRAY8)

Any ideas how to proceed?
identity reports images (which is my pipeline image counter)...

Thanks a lot!

Best regards,

Erik






Erik Rull wrote:
> Hi Josh,
> 
> thanks for the fast reply - and yes, I also understood it that way that the shm
> is just a memory buffer of "whatever goes in, goes out".
> 
> Josh Doe wrote:
>> You shouldn't have to convert to BGRx to use shmsrc/shmsink, those elements
>> don't even really have the concept of video, they're agnostic to it, they just
>> see buffers that need to be sent. Can you share your sending and receiving pipeline?
> 
>> Shared memory is zero-copy, so has the best performance. What kind of throughput
>> are you using? And what platform?
>>
>> -Josh
> 
> CPU is an IMX embedded device, the rest is kind-of LFS.
> 
> My pipeline parts look like this - the appsrc / appsink encapsulates some image
> processing (special overlay, reformatting, etc.) that I could not solve with
> gstreamer - the processing time is far less than 100msec inside and the output
> is grayscale:
> 
> aravissrc camera-name=x.x.x.x num-buffers=10 exposure=100000 gain-auto=0 !
> video/x-raw,format=GRAY8,width=640,height=512,framerate=8/1 ! videoconvert  !
> videobalance contrast=1.4 brightness=-0.3 contrast=1.8  ! videoconvert  !
> video/x-raw,format=GRAY8 ! appsink name=sink max-buffers=10 drop=1
> 
> appsrc name=src stream-type=0 is-live=1 max-bytes=10000000
> caps=video/x-raw,format=(string)GRAY8,framerate=8/1,width=401,height=404 !
> shmsink render-delay=0 socket-path=/tmp/pad_shm shm-size=10000000
> wait-for-connection=0 max-lateness=500000000 buffer-time=0
> 
> shmsrc socket-path=/tmp/pad_shm is-live=1 !
> video/x-raw,format=(string)BGRx,framerate=(fraction)8/1,pixel-aspect-ratio=(fraction)1/1,interlace-mode=(string)progressive,width=401,height=404
> ! videoconvert  ! identity name=identity ! ximagesink max-lateness=500000000
> name=sink
> 
> Maybe I have additional errors somewhere else in the pipeline...
> 
> But due to the fact that my appsrc exposes an 8bit image, I would not expect
> shmsrc to get out something differently...
> At the end - the displayed image is actually grey :-)
> The identity at the end I use to count the number of images displayed.
> I generate some additional output between appsink and appsrc if I map that right
> beside the image, the image is delayed by ~ 2 seconds...
> 
> Thanks!
> 
> Best regards,
> 
> Erik
> 
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