Talk:Porting Theora to 353 cameras

Ok, I started a new page on the Theora project in 353 cameras. I started with a global approach and a list of modules that need to be changed or replaced on the 353 model. Feel free to correct me or add suggestions as I'm not (yet...) an expert on Elphel cameras. I think the first step is to make an exhaustive list of the hardware blocks that need modifications and then detail what need to be done in each block. --JeremViewsurf 03:48, 19 February 2008 (CST)

As I understand your first need is not a streaming but producing a small video clip to be uploaded via FTP. This can be done more easy with minimal non FPGA modifications.

We will probably create a CVS branch for your port, to be able to test it we need to compile a standard 7.1.x firmware disabling everything sensor or FPGA related and change the FPGA bitstream. --Alexandre.Poltorak 07:53, 19 February 2008 (CST)

You mean that it should be possible that the system can handle software Ogg Theora encoding for a non real-time application such as producing small video clips ? I'm aware that it depends on the output resolution, framerate and length of the clip but does a 1 min 1024x768 @ 25fps clip for example can be processed in a reasonable delay ? I'll discuss with Viewsurf's development team in order to obtain more precise specs concerning video output (in terms of length, resolution, framerate and encoding delay acceptable) but if you can give me an idea of what the software part can handle, I would consider spending more time in soft Theora transcoding instead of FPGA design. --JeremViewsurf 03:37, 20 February 2008 (CST)

No, sorry i was not speaking of transcoding. It would take too much calculation power and is not possible on the camera's CPU. The Theora encoding should be done in FPGA. What i was speaking about is the software part.. I think you do not need a streamer for the first steps. You only need to generate a clip in the FPGA memory, and upload it to a FTP. --Alexandre.Poltorak 08:32, 20 February 2008 (CST)

Some questions concerning changes in the FPGA :

• Is it necessary to keep histogram and timestamp blocks in a design which supports Theora only ?
• Is it possible to keep channel 0, 1 and 3 design without changes in the memory controller ?
• The 353 design uses 2 DMA fifos between the compressor and the system interface instead of one in the 333 design. Is it possible to keep only one 333 DMA fifo in the final design ?
• In the 353 design, all signals and blocks I/O concerning 90° phase clock are commented. Is it possible to uncomment them in order to restore the clock ?
• Motion compensation seems not to be implemented in the Theora compressor yet. Is it possible to add this feature later in the compressor block without major changes in the final design ?

--JeremViewsurf 02:43, 25 February 2008 (CST)