I am wrong, the bandwidth = 166M*4*32bit/8 = 2656MBytes/s
huahua5 2008-08-01 发件人： huahua5 发送时间： 2008-07-31 10:22:38 收件人： Panchy Rivas; [EMAIL PROTECTED] 抄送： 主题： Re: 4 video capture and SMP-linux support ddr2 theorical bandwidth = 297M * 4 * 32bit/8 = 4752MBytes/s because of delay ,bandwidth = 4752*0.4 = 1900MBytes/s 4 channels D1(720x480) data = 720 * 480 * 2 * 30frames/s * 4 channels = 82944000Mbytes/s = 81MBytes the data save to DDR2 and load to cpu to process,meanwhile,send to OSD to display,so the least times is 3. so the least data rate = 81M * 3 = 243MBytes I think dm6446 DDR2 can support the bandwidth requirement. maybe something I make wrong. huahua5 2008-07-31 发件人： Panchy Rivas 发送时间： 2008-07-30 22:59:04 收件人： davinci-linux-open-source@linux.davincidsp.com 抄送： 主题： 4 video capture and SMP-linux support So can the DDR memory be changed to support the bandwidth? Does anyone have any suggestion. What I am trying to do is have 4 video source and at any one time recoded 1 channel to disk while displaying another on the monitor and if possible also be able to display a quad view of all 4 channels on the monitor display. Jon Povey wrote: > I don't know about DM6446, but on DM355 the limiting factor is DDR > memory bandwidth. same for the 6441/6446, the limiting factor is DDR bandwidth, not CPU/DSP/DMA speed. > I tried to capture two sync locked 8-bit BT.656 > streams side-by-side as 16-bit input and use DMA to separate them for > display. It worked, but there was not enough DDR memory bandwidth to do > this and output the image with an OSD enabled - VPBE was starved of data > and lots of tearing / visual artifacts appeared. > > Not sure if you will have the same issues but it's something you might > want to be aware of. > > -- > Jon Povey, Design Engineer > jon.povey at racelogic.co.uk | +44(0)1280 825983 > > > > ------------------------------------------------------------------------ > *From:* davinci-linux-open-source-bounces at linux.davincidsp.com > [mailto:davinci-linux-open-source-bounces at linux.davincidsp.com] *On > Behalf Of *Panchy Rivas > *Sent:* 24 July 2008 20:18 > *To:* davinci-linux-open-source at linux.davincidsp.com > *Subject:* 4 video capture and SMP-linux support > > I am working on a similar system. I just got the DM6446EVM today so > I am just getting started. I was thinking because the front end > video port can be 1280 pixels per horizontal line then 2 channels > (minus a little bit on the edges) can fit side by side to process 2 > channels. If you include the interlace artifact remover then we > could actually fit 4 channels. The TVP5154 could be used as the > decoder to a FPGA then to the DM6446. > > > > Please if anyone has done this or similar please let me know if > there is enough resources to do this. > > > > Thank you, > > Panchy > > > > Racelogic is a limited company registered in England. Registered number > 2743719 . > Registered Office Unit 10, Swan Business Centre, Osier Way, Buckingham, > Bucks, MK18 1TB . > > The information contained in this electronic mail transmission is > intended by Racelogic Ltd for the use of the named individual or entity > to which it is directed and may contain information that is confidential > or privileged. If you have received this electronic mail transmission in > error, please delete it from your system without copying or forwarding > it, and notify the sender of the error by reply email so that the > sender's address records can be corrected. The views expressed by the > sender of this communication do not necessarily represent those of > Racelogic Ltd. Please note that Racelogic reserves the right to monitor > e-mail communications passing through its network > Thanks Panchy Rivas
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