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Hi!
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<div class="">It is possible to do what you want to do. We do that, and more. Have a look at the ffmpeg-dev forums. There are some pretty interesting discussions about how to use your own cuda context, and even your own cuda stream.</div>
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<div class="">Good luck!</div>
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<div class="">Oscar<br class="">
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<div class="">El 23 maig 2018, a les 8:24, joep <<a href="mailto:joep@groovytunes.nl" class="">joep@groovytunes.nl</a>> va escriure:</div>
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<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class="">Hello,</span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><br class="">
</span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class="">I am trying to create a program that does the following:<br class="">
</span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class="">1. decode frames with cuvid</span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class="">2. run CUDA kernels on the decoded frames</span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class="">3. encode result with nvenc</span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><br class="">
</span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class="">In order to do step 2, I need the CUDA kernels to access the decoded frame which should be stored in the GPU memory.</span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class="">For this I think I need to provide the CUDA CUcontext to ffmpeg and give the pointer to the decoded frame to the kernel.</span></div>
<p style="padding: 0; margin: 0;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""></span></p>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class="">I could not find any documentation about this topic.<br class="">
</span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class="">In the ffmpeg docs I see the AVCodecContext has hw_device_ctx which is a </span><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class="">AVHWDeviceContext.</span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><span style="font-family: tahoma, arial, helvetica, sans-serif; font-size: 13.3333px;" class="">AVHWDeviceContext has
a hwctx field which can be a AVCUDADeviceContext.</span></span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><span style="font-family: tahoma, arial, helvetica, sans-serif; font-size: 13.3333px;" class="">AVCUDADeviceContext has
a cuda_ctx field which is a CUcontext.</span></span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><span style="font-family: tahoma, arial, helvetica, sans-serif; font-size: 13.3333px;" class=""><br class="">
</span></span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><span style="font-family: tahoma, arial, helvetica, sans-serif; font-size: 13.3333px;" class="">So I think I need to
create a AVHWDeviceContext and set it on the </span></span><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><span style="font-family: tahoma, arial, helvetica, sans-serif; font-size: 13.3333px;" class="">AVCodecContext
before calling avcodec_open2.</span></span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><span style="font-family: tahoma, arial, helvetica, sans-serif; font-size: 13.3333px;" class="">Are my assumptions right?</span></span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><span style="font-family: tahoma, arial, helvetica, sans-serif; font-size: 13.3333px;" class="">And how can I create
a AVHWDeviceContext with the correct hwctx?</span></span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><span style="font-family: tahoma, arial, helvetica, sans-serif; font-size: 13.3333px;" class=""><br class="">
</span></span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><span style="font-family: tahoma, arial, helvetica, sans-serif; font-size: 13.3333px;" class="">Thanks,</span></span></div>
<div style="padding: 0px; margin: 0px;" class=""><span style="font-size: 10pt; font-family: tahoma, arial, helvetica, sans-serif;" class=""><span style="font-family: tahoma, arial, helvetica, sans-serif; font-size: 13.3333px;" class="">Joep</span></span></div>
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