Copy data from H264 decoder output consumes too much time

bing liu

Hi,

I need to copy the Decoder output data to the buffer which is allocated in shareregion 1 using Memory_alloc(). I do as follows:

1. get the virtual addr from physical addr using OSA_mapMem()

2. use memcpy to copy data from virtual addr to shareregion buffer.

I copy 640x480 bytes each time, and it needs more than 5ms to do so. But if I copy the same number of data from the buffers both in A8 side or both in shareregion or A8->shareregion or shareregion->A8, it just needs 0.5ms or so. I could not understand why the run time varies so much.

Could someone know that?

Thanks in advance! Appreciate for your reply!

over 11 years ago

0 Badri Narayanan over 11 years ago

TI__Guru 59700 points

The poor performance is because OSA_mamMem maps the buffers to user space as uncached pages. You will see 10X degradation in performance due to this. You can use EDMA if your destination is a sharedRegion buffer (Physically contiguous).That is the preferred method to copy video frames.

0 bing liu over 11 years ago in reply to Badri Narayanan

Expert 2900 points

Hi Badri,

Thanks for your reply! Could I use OSA_dma API to copy data? And could you give some example?

0 Badri Narayanan over 11 years ago in reply to bing liu

TI__Guru 59700 points

You can refer /dvr_rdk/demos/mcfw_api_demos/mcfw_demo/demo_vcap_venc_vdec_vdis_bits_rdwr.c for DMA usage. Pls refer the OSA_dma API documentation for 2D frame copy. Also you can search the e2e forum where several others have used the OSA_dma APIs with DVR RDK/ IPNC RDK.

0 bing liu over 11 years ago in reply to Badri Narayanan

Expert 2900 points

Hi Badri,

Thanks so much! Now I could copy data using OSA_dma API and the efficiency enhances more than 10 times.

0 Holger Eberhard102906 over 7 years ago in reply to bing liu

Genius 4570 points

Hi,

we use DM8168 custom design based on DVRRDK 3/4.

I also want to copy decoded frames to a buffer.

Currently for me it is not clear where I can access the decoder output buffer.

Any idea where we can get the decoder output?

Best regards

Holger

0 Prashanth Kumar15 over 7 years ago in reply to Holger Eberhard102906

Mastermind 8775 points

Hi Holger,

Please refer the H264 Decoder user guide ( https://git.ti.com/ivimm/ipumm/trees/master/extrel/ti/ivahd_codecs/packages/ti/sdo/codecs/h264vdec/docs ). It will answer your query. What version of Codec are you using?

0 Holger Eberhard102906 over 7 years ago in reply to Prashanth Kumar15

Genius 4570 points

Hi Prashanth Kumar,
Thanks for reply.
We use decoder 500.V.H264AVC.D.HP.IVAHD.02.00

Meanwhile a new requirement appears, we also need access to the capture frame buffers.
Our application is using MCFW, our usecase is multich_progressive_vcap_venc_vdec_vdis.
So the idea was to extend LIVE_DECODE_DUP with an extra output and get access to 16 capture and 16 decoded channels.
But currently I have no concept how to get the buffer after the dup.

0 Prashanth Kumar15 over 7 years ago in reply to Holger Eberhard102906

Mastermind 8775 points

Holger,
I would request you to open new thread for this question, so the actual experts get notified for quicker resolution of the query.
The latest Codec Version is 02.00.21.00, recommend you to use this.

0 Holger Eberhard102906 over 7 years ago in reply to Prashanth Kumar15

Genius 4570 points

Prashanth,
Ok, You are right.
Regards Holger

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Copy data from H264 decoder output consumes too much time