Thanks for you reply. The SOC is still under development stage, it's not a product yet. And a small mistake I've made, the tuner will not integrated into the SOC. The demod might be. Some more questions: As far as I know, relationship between demod and decoder is the buffer used as demod output(also the input for a/v decoder), and maybe a shared interrupt used to catch some misc event from tuner/demo/av decoder(a interrupt status register will be used to determine who cause it). Do you think this will be a problem if I write individual drivers? And would you please tell me that is the "memory-to-memory decoding" for? Best regards Michael Qiu 2010/1/14 Hans Verkuil <hverkuil@xxxxxxxxx>: > Hi Michael, > >> Hi guys, >> I'm going to write drivers for a new soc which designed for dvb-s set >> top box. >> It will support these features: >> 1. Multi-layer display with alpha blending feature, including >> video(YUV), OSDs(2 same RGB layers), background(with fixed YUV color) >> and still picture(YUV color for still image) >> 2. DVB-S tuner and demod >> 3. HW MPEG2/4 decoder >> 4. HW accelerated JPEG decoder engine. > > Interesting device. Which SoC is this? > >> >> My targets are: >> 1. Fit all the drivers in proper framework so they can be easily used >> by applications in open source community. >> 2. As flexible as I can to add new software features in the future. >> >> My questions are: >> How many drivers should I implement, and how should I divide all the >> features? >> As far as I know: >> A) a frame buffer driver for 2 OSDs, maybe also the control point for >> whole display module? >> B) video output device for video layer, which will output video program. >> C) drivers for tuner and demo (or just a driver which will export 2 >> devices files for each?) >> D) driver for jpeg accelerate interface, or should it be a part of >> MPEG2/4 decoder driver? >> E) driver for MPEG2/4 decoder which will control the behave of H/W >> decoder. >> >> Actually I think all the display functions are relative, some >> functions i listed upper are operating one HW module, for instance: >> OSD and video layer are implemented by display module in H/W level. >> What's the right way to implement these functions in driver level, >> united or separated? >> And, I've read some documents for V4L2, but I still cannot figure out >> where should I implement my driver in the framework. >> >> In a word, I'm totally confused. Can you guys show me the right way or >> just kick me to a existing example with similar features? > > The driver that comes closest to this in terms of functionality is the > ivtv driver. That driver supports MPEG2 encoding and decoding, an OSD and > raw YUV input and output. > > There are several ways you can design devices like this, but the way ivtv > is designed is that there is one master driver (ivtv) that handles all the > encoding and decoding, and the framebuffer driver that you need for the > OSD is just an 'add-on' module that provides the FB API but internally > talks to the master driver. > > The tuner/demod part is usually integrated in the master driver. See the > cx18 driver for example. But it is probably also possible to implement it > as a separate driver in a similar manner as a framebuffer driver. > > Generally the key criteria on how to design drivers like this is the > hardware design: for example, if the tuner/demod part is completely > independent from the decoder part, then it is possible to write completely > independent drivers as well, but if they share hardware components (e.g. > the interrupt handling hardware), then you usually have to combine > functions in one driver. > > Note that some features that you probably need (such as memory-to-memory > decoding) are not yet implemented in V4L2 (although work is in progress on > this). > > Regards, > > Hans > >> >> >> Best regards >> Michael Qiu >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-media" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > > -- > Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom > > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
