How many chips of DM8168 do I need?

Hi,

DM8168 can do 3 channels of 1080P60 encode or 3 channels 1080P60 decode. So it can effectively do 1920*1080*60*3 pixels processing. I think 1024X768 is quite less than this like (1024*768*60*4)+ (720*576*30) < (1920*1080*60*3). So one DM8168 should be enough for your case.

Regards,

Hardik Shah

Hi Hardik Shah:

    THe HDVICPs are independent,are you sure the caculation like this(1024*768*60*4)+ (720*576*30) < (1920*1080*60*3) is correct?

If one DSP can process this 5 video ,how can I interface to DSP,and is there a diver like this?

Thank you

Hi,

If you are using EZSDK, we have a scheduler for scheduling the channels based on load of HDVICP. So this is possible. Each HDVICP can handle more than 1 channel based on load like each can handle 8 channels of D1 or 1 channel of 1080P@60.

Regards,

Hardik Shah

Hi,

Since 2 1024x768 is less than one 1080p, it can be processed in single HDVICP. with 3 HDVICP you can do your use case.

Regards

Vimal

HI, HardikShah:

    I know that I can multiplex video stream into HDVPSS of DM8168,but I find less information about this in the doc "sprugx8_dm816x_vpss.pdf"

I want to know the rules about multiplexing video stream into HDVPSS ,for example can I multiplex a 1024x768@60 and D1 into 8bit VIP of HDVPSS?

I also want to know performance of the encoder and decoder ,

is it correct that

 no matter how many channels of the video I pass them into DM8168,if the bit rate of  them is less than 1080x1920x60x2x3 Byte, so they can be encode(or decode )to H

.264 by DM8168???

Hi,

Answers inline,

le lemon said:

I want to know the rules about multiplexing video stream into HDVPSS ,for example can I multiplex a 1024x768@60 and D1 into 8bit VIP of HDVPSS?

Multiplexing is achived using some special hardware. You can refer to TVP5158 decoder on how multiplexed stream is pumped into HDVPSS VIP. TVP5158 specs could be found at http://www.ti.com/lit/ds/symlink/tvp5158.pdf. Multiplexing is done upto 4 channels per VIP port as long as combined pixel clock of all 4 channels doesn't increase than 165MHz. But we have never tried this type of combination like XGA and D1.

le lemon said:

I also want to know performance of the encoder and decoder ,

Each HDVICP can do 1080P60 in DM8168. Now theoritically it should be able to do N channels if combined pixels of N channels are less than pixels in 1080P60. But there will be software overhead as number of channels increases. So you should consider that software overhead also.

Regards,

Hardik Shah

I have a question about encode/decode data rates

- if I have 2 channels of 1080p H264 decode running, and one channel of 1080p H264 encode running, what data rates can be supported?

- i.e. if I have 2 50MBit H264 streams coming from SATA, output as video, and 1 1080p Video Input, and want to encode to 50MBits, and stream out

- is this supported, i.e. feasible on the DM8168?

Also, do the H264 codecs support 4:2:2 encode / decode or just 4:2:0?

Regards,

Phil

Phil

Yes, with one DM8168 you can do the following

• 2ch of 1080p60 50Mbps decode
• 1ch 1080p60 50Mbps encode

H264 encode and decode supports only 420  as data format

regards, shiju

Thanks for the reply

- it there an upper practical limit to the Bitstream rate?

- or is the compressed rate always considered to be small fry compared to the uncompressed video rate, and therefore is not usually the bottle neck?

- for example, in my use case above, what would be the likely upper limit on the bit rates? This would set an upper limit on the quality.

Are these data rates possible with the standard clock rates for the DM8168?

- or are some setups needed via Uboot to achieve these? (i've seen other thread posts advising Uboot tweaks for the DM8148, so I'm not sure if these are needed for the DM8168.)

And finally, can my use case above be done using gstreamer, or is it necessary to go to OMX for multiple stream use-cases such as this?

Thanks,

Phil

Phil

>>>- it there an upper practical limit to the Bitstream rate?

>>>- or is the compressed rate always considered to be small fry compared to the uncompressed video rate, and therefore is not usually the bottle neck?

[shiju] i do not think so, But I am very not sure, will check and let you know

>>>- for example, in my use case above, what would be the likely upper limit on the bit rates? This would set an upper limit on the quality.

[shiju] We have observed 20Mbps itself give really good quality. So 50Mbps would be really good enought

Are these data rates possible with the standard clock rates for the DM8168?

[shiju] yes, 2ch of 1080p60 50Mbps decode + 1ch 1080p60 50Mbps encode would be possible even with standard clock rates.  

- or are some setups needed via Uboot to achieve these? (i've seen other thread posts advising Uboot tweaks for the DM8148, so I'm not sure if these are needed for the DM8168.)

[shiju] for certain application we hike these clocks to achieve some stretch goals

And finally, can my use case above be done using gstreamer, or is it necessary to go to OMX for multiple stream use-cases such as this?

[shiju] I am not sure this can be done with gstreamer or OMX f/w.  DM8168 IPs (mainly HDVICP) is good enough for your usecase, but you have to be very careful on any overhead added by gstreamer or OMX.  DM8168 has multi-core architecture and  especially the Non tunneled way of data processing across cores is critical

can you please elaborate on your usecase with end App and dataflow?

Hi Shiju,

I'm evaluating the DM8168 for possible use in future product(s), so I am trying to find out what quality levels, and performance levels are possible with the chip

- and what additional performance would be left over to make use of the other functions of the chip, such as GPU, PCIe and so on.

I am worried that you say that gstreamer and OMX aren't efficient enough to allow my use case to be implemented on the DM8168

- these are the tools recommended for the job by TI, aren't they?

My use case is just a simple scenario to utilise the three codecs at 1080p - two decode streams and one encode stream. The decodes would be output on two VOUT channels, and the encode stream uses a VIN.

- it sounds like the DM8168 is limited by the A8 and the DSP rather than the Codec performance - is this a correct interpretation?

Anyway, I need to understand the limitations, and understand when a C6678 would be a better choice, and when a combination of DM8168 + C6678 is the better choice

Phil

Phil

Yes, OMX and Gstremer are recommended by TI, but we have seen this is not a good choice for multichannel system.  If you need only 2decode + 1 encode, these might still work with  OMX and Gstremer . i want to understand more about your end product

we have created another proprietary frame work called "MCFW RDK" mainly for high channel density surveillance App.  let me first understand your App before choosing the framework

>>>- it sounds like the DM8168 is limited by the A8 and the DSP rather than the Codec performance - is this a correct interpretation?

A8 can run @1200MHZ and DSP can be configured at 1000MHZ, so i think this should be good enough for your App.  Can you give more details on your product, i mean what is the end product and what all functionalities to add on A8 and DSP

Regards, shiju

Hi Shiju,

It looks like the MCFW RDK (DVR RDK?) is the thing we need

- not the udworks RDK - don't need the full DVR App.

- need to support multiple streams of 1080i/60 or 1080p/60 - at 20+Mbits....

- Video I/O would be interfaced through FPGA

Assuming the MCFW RDK supports HD Video at these data rates, is this the route you would recommend for multi-stream HD encode/decode?

- where can I download it from?

(we have DM8168 EVM already)

Thanks,

Phil

Phil,

It would help if you can describe the use case in detail. Have you looked at EZSDK ? It has examples of HD encode/decode/capture/display. You can evaluate that for your use case.

Regards

Vimal

I have the EZSDK

- the EZSDK provides OMTB & gstreamer demos of Endode/decode

- so this is a good start

- the Encode is set to run at 10Mbps, so the quality is not very good

- when I set the OMX demo to encode @ 20Mbps, the system began dropping frames. In fact anything above about 12-15Mbps seemed to be dropping frames.

My use case in 1080p/60 would typically be 2 x 1080p/60 encode, 1 x 1080p/60 decode.

When operating in 1080i/60, I can feed more channels though the VIN & VOUT buses, but for practical purposed, I'm unlikely to want more than 2x 1080i/60 Encode, and 2 x 1080i/60 Decode, same for 720p

- so the 1080p/60 use case needs more performance.

I would like to be able to support higher quality than I can see on the demo h264 file.

I don't understand why multi-channel support seems to be such an issue given that the DM8168 is inherently a multi-channel device.