Il giorno venerdì 7 febbraio 2014 10:14:38 UTC+1, [email protected] ha scritto: > > On Wednesday, February 5, 2014 6:02:02 PM UTC+1, Jon Smirl wrote: > > On Wed, Feb 5, 2014 at 9:01 AM, Enrico <-> wrote: > > > > > Il giorno martedì 4 febbraio 2014 16:29:24 UTC+1, Jon Smirl ha > scritto: > > > > >> > > > > >> Does anyone have a setup which works for viewing a live image from > the > > > > >> csi camera on the display? Something like cheese? > > > > >> > > > > >> I tried doing this on the A20 with non-accelerated video drivers and > > > > >> the system is not fast enough to keep up with the output from the CSI > > > > >> camera. Cheese just gives me a black rectangle and lots of errors out > > > > >> of the camera drivers. > > > > >> > > > > >> I want to work on the CSI driver but I need to be able to see what I > > > > >> am doing. When the display system isn't fast enough everything gets > > > > >> complicated because of dropped frames. > > > > >> > > > > >> It also doesn't work to save the video stream to SD Card or the > > > > >> network, neither is fast enough. > > > > >> > > > > > > > > > > Did you try saving it to a tmpfs (usually /tmp or /dev/shm) ? That's > the > > > > > fastest place you can save to. > > > > > > > > Uncompressed video is gigabytes in size > > I might be blunt. You want unencoded video output. Cedar and or Cedarus > can only help with scaling. > > When compressed video is played it get's uncompressed resulting in the > same amount of gigabytes. So those shouldn't be the problem. > > I guess the problem is in the path between input and output. If the video > player taps directly into the CSI stream there shouldn't be a problem. > > I guess the issue that the stream gets copied to userspace and than send > back to kernalspace. Which gets limited by CPU and RAM speed, these perform > the copy actions and need to track delays, dropping frames, etc. > > Generic copy free would require something like DMA access. But such a > generic userspace connected framework is quite new, DMA-BUF. > > For now I guess you are limited to directly encode the output stream > before playback. Usually the encoders are dirctly, copy free, connected to > the inputstream. Which limits memory en cpu strain by only needing handle > the compressed stream > > So you need a player that can directly tap into the video stream and > deliver it copyfree to the output device. > > Or a DMA-BUF capable CSI+Display driver and player to match. > > You can try to adapt [1] for csi input. What it does is to just set the display buffer address to the tvd buffer, so no buffer copying. It should work with csi too.
Enrico [1]: https://github.com/ebutera/sunxi-tvin -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
