topic Re: Decoding of multiple H.264 streams simultaniously in i.MX Processors

Decoding of multiple H.264 streams simultaniously

MicMoba — Thu, 25 Jun 2020 13:32:17 GMT

I want to decode up to four H.264 (BaseLine) streams simultaniosly and show them on a LVDS display.

I found a table in a NXP document (DWF14_APF_IND_T0208.pdf) that the VPU can decode up to 8 D1@30fps.

Is it also possible to mix up the stream formats? For example 2 D1@30fps an 2 720p@30fps?

In a simple test I let stream three cameras with 720p@30fps. Two of these cameras are the same type. The third is a different one. I decode and show them with gstreamer. If I use 2 cameras everything is fine but when I connect the 3rd camera the display stucks.

This happens always when I connect the camera that is another type.

I figgure out that this camera always sent BaseLine@L4.1 independent of the resolution. I read in a forum that the decoder take the profile and level information to initialize the decoder.

So my question: Is it possible that the VPU reach its bounds when this one camera streams BaseLine@L4.1 and so the whole decoding stucks?

The attached table say that the VPU only can decode 1 stream with 1080p@30fps. That's what BaseLine@L4.1 mean.

Thanks

Michael

Re: Decoding of multiple H.264 streams simultaniously

Bio_TICFSL — Fri, 26 Jun 2020 15:13:53 GMT

Hello Michael,

In the i.MX6 The VPU is able to support 1 decode at 1080p@30fps, In the MX8M it can support 4Kp30 (h.264), 1080p60.

Regards

Re: Decoding of multiple H.264 streams simultaniously

MicMoba — Mon, 29 Jun 2020 03:56:04 GMT

Yes but how much is the effect of the profile and level to the decoder capacity? 1080p@30fps matches Baseline profile and level 4.1

If now the stream source always send Baseline@L4.1 independent of the real resolution because of an issue can this cause a "overload" of the VPU if a second steam comes in?

Re: Decoding of multiple H.264 streams simultaniously

Bio_TICFSL — Tue, 30 Jun 2020 14:14:13 GMT

Hello,

The second stream will caused overload.

Please refer to “i.MX_Linux_User's_Guide.pdf”.

“Video playback to multiple displays can be supported by a video sink plugin.

To configure the video sink plugin for multidisplay mode, see Overlaysink usage

later in this document.”

It makes sense to use the recent BSP.

i.MX 6 Series Software and Development Tool|NXP

Regards

Re: Decoding of multiple H.264 streams simultaniously

MicMoba — Tue, 30 Jun 2020 19:12:56 GMT

Hi Bio_TICFSL,

thanks for reply. What is your understanding of multiple displays? To show several streams or outputs on one display (monitor) or show one stream or output on more than one display (monitor)?

Regards

Re: Decoding of multiple H.264 streams simultaniously

Bio_TICFSL — Wed, 01 Jul 2020 14:16:26 GMT

Hi Michael,

To have several stream and output on one display or different display.

Regards