Re: [linux-dvb] RE : linux-dvb and Dektec [was: DVB API update]
hi, ehi, what a thorough explanation.. maybe things are not all this black and white.. i wrote my first answer a bit quickly but now i'd like to give two more bits for added value! Thierry Lelegard wrote: Also, as you pointed out, Dektec products can be either input, output or both. Their output products also include very nice modulators on PCI boards. I presently use a DTA-110T, a DVB-T modulator. Since linux-dvb is an input-only framework, it would address only part of Dektec products (and even part of a device in the case of a DTA-140). indeed, the fact of the linux-dvb driver to be actually an input only framework for MPEG (TS/PS) stream it's beginning to fall a little short. IMHO there are already a number of stuff and environment, old and newer, that need to be addressed, on linux, with an outgoing path for native MPEG streams. historically there were two devices with such a capability: - the Fully Fledged (nexus) cards with their MPEG2 decoder on board - the ancient REALmagic Hollywood Plus - actually there is also the MPEG2 decoder inside the iTVC15 / CX23415 chip in the PVR350 card.. (ivtv driver not coping with it, i think..) then, there's the big mess of video decoding of MPEG2 PES stream (SD/HD) and some acceleration for H264 stream inside the core of the recent GPUs (avivo and purehd marketing vaporware.. something from via and intel too..) are we going to leave this feature available as a sub-set of the X driver or there's a place for a MPEG driver without the X? i think for example to use-cases like the media center like myth-tv running with DirecFB.. in a bit different scenario, the embedded one, there are also devices natively decoding MPEG2 TS streams like: - the PowerPc SoC inside some DVB SET TOP BOX as Dreambox and the DGStation CubeCafe (Vulcan and Pallas) they do have actually a linux kernel running on the powerpc core but the decoding API are a bit home made and binary too (maybe thing are changing..) BTW we are a bit involved in a design of an open source java based middleware running on such HW so we are really using it and would prefer linux-dvb drivers for MPEG decoding.. - i really don't know how are coping with DVB decoding inside the other big player of the linux-based STB market, the Sigma Designs EM863x. - and then there is the third player, STM ST710x who's running linux too with some DVB hack for decoding purposes.. IMHO plenty of situations where a linux dvb API for decoding stuff should/could be useful for the masses, because this generation of STBs are flooding our houses today or tomorrow, so we need and should have a way to hack them.. [..skipping lot of things about userland against kernel stuff..] Anyway, coming back to linux-dvb and Dektec, kernel drivers exist for both, just write userland code to access the one you want. then i'd like to add some bits about the professional market using DVB ASI interfaces. as someone already have told, there are plenty of DVB card producers; i can say out of my mind these: dektec, videopropulsion, optibase, dveo/computermodules, alitronika, bluetop (and other too..) all these cards are of course running on linux today, but each with is own driver API.. i think only dektec is the one with open source driver openly available on the site and i know that some chinese are providing drivers with wrapper to mimic the dektec API. that's how i see this market. I don't know IF there's interest for the linux community at large to promote a unified driver for this technology.. in theory, the professional customers of such cards should be interested to get a single unified compatibility layer to escape the vendor lock in, BUT, if they are fine as they stay today, why the linux community should give them an hand? i don't think we would get back something useful in the short term, but i'm open to hear other opinions too.. bye andrea venturi -Thierry -Message d'origine- De : [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] De la part de Andrea Venturi Envoyé : mercredi 3 octobre 2007 15:10 À : linux-dvb Objet : Re: [linux-dvb] DVB API update Manu Abraham wrote: Hi, Simon Hailstone wrote: Hi All, If it sheds any light on the nature of DVB-ASI, there are Linux drivers available ( with source ) for the DekTec ASI adapters here : http://www.dektec.com/Products/LinuxSDK/Downloads/LinuxSDK.zip If someone has the hardware, we can take a go at it. hi, here in Cineca, we are running an open source project called JustDvb-It, it's a DVB DSMCC carousel server for interactive television, you could grab it here: http://www.cineca.tv/labs/mhplab/JustDVb-It%202.0.html as we need to interface broadcaster stuff like multiplexer (with DVB ASI interfaces), we use plenty of these Dektec card like DTA140 and so on.. but for that purpose we found sufficient the driver provided by Dektec. it's a simple character device with some
Re: [linux-dvb] RE : linux-dvb and Dektec [was: DVB API update]
Andrea Venturi wrote:
- the PowerPc SoC inside some DVB SET TOP BOX as Dreambox and the
DGStation CubeCafe (Vulcan and Pallas)
they do have actually a linux kernel running on the powerpc core but the
decoding API are a bit home made and binary too (maybe thing are
changing..)
The PowerPC-based Dreamboxes still use the old DVB-API (its initial
drivers predate the change to the new API, and never followed it),
whereas the newer Dreamboxes (DM7025 and the hopefully upcoming DM8000)
are using the current API. (There was also an effort to build new
Pallas/Vulcan APIv3 drivers as GPL, but this had to be pulled for legal
reasons. Those drivers were never complete, though.)
All are using binary-only driver modules for different reasons, but all
conform to the available userspace API as much as possible. Sometimes a
few additions were required (see also my discussion about
VIDEO_GET_{PTS,STC} etc.), but they use (for example) the
/dev/dvb/adapter0/video0-API.
Another implementation is the dbox2, which uses open-source drivers. And
don't forget the old full-featured cards.
However sometimes the API is not completely clear (like the order: Do
you first have to do a VIDEO_PLAY, then start the demux? Things like
that are sometimes even hardware-dependent and are likely to differ from
implementation to implementation. Sometimes you need to be tricky for
proper syncing, and trickmodes are a completely gray area...) But for
just playing video, the API should be ok. Don't forget that all hardware
MPEG decoders are beasts, and likely to be tricky in operation. The API
should hide the ugly details, but that's not always possible.
Felix
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Re: [linux-dvb] RE : linux-dvb and Dektec [was: DVB API update]
Felix Domke wrote: Andrea Venturi wrote: - the PowerPc SoC inside some DVB SET TOP BOX as Dreambox and the DGStation CubeCafe (Vulcan and Pallas) they do have actually a linux kernel running on the powerpc core but the decoding API are a bit home made and binary too (maybe thing are changing..) The PowerPC-based Dreamboxes still use the old DVB-API (its initial drivers predate the change to the new API, and never followed it), whereas the newer Dreamboxes (DM7025 and the hopefully upcoming DM8000) are using the current API. (There was also an effort to build new Pallas/Vulcan APIv3 drivers as GPL, but this had to be pulled for legal reasons. Those drivers were never complete, though.) A while back i had asked Amino communications for the driver/kernel sources, when their STB wasn't able to do MPTS properly. The reply i got was pay up $50,000 and you get the sources. Manu ___ linux-dvb mailing list linux-dvb@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
[linux-dvb] RE : linux-dvb and Dektec [was: DVB API update]
IMHO, the Linux DVB framework serves two main purposes: - Common API for the zillions of DVB-S/C/T adapters - Common frontend for TV watching programs such as Myth et al. Dektec products address the market of professional test lab applications using ASI input/output, QPSK/QAM/OFDM modulators output. They address separate needs, separate usage. I have been using both linux-dvb and Dektec products for years and found no real use in integrating both. Also, as you pointed out, Dektec products can be either input, output or both. Their output products also include very nice modulators on PCI boards. I presently use a DTA-110T, a DVB-T modulator. Since linux-dvb is an input-only framework, it would address only part of Dektec products (and even part of a device in the case of a DTA-140). I develop and use test lab applications for my own usage. I need to receive and send transport streams. I have my own TS processing framework in userland, with input and output plugins (such a trendy term ;-). I have separate input plugins for linux-dvb and Dektec. I have a Dektec output plugin, but none for linux-dvb of course. This is of course a specific professional usage, not a home TV-watching program. Who's going to watch TV at home from an ASI feed ? I think that remaining in userland is better approach for that. At the beginning, before I really understood I went the wrong way, I developed a loopback linux-dvb frontend. It was a kernel driver which integrated with linux-dvb and that was fed by userland applications. The TS coming from these userland applications was presented as coming from a linux-dvb device. Since there is no generic frontend class, my driver pretended to be a QPSK frontend and silently ignored tuning requests. So, a userland application could read a TS from anywhere (a Dektec device, a file, IP multicast, whatever) and feed the dvb loopback driver. Then, any linux-dvb application was able to play with this TS. But, apart from the useless pride of being a kernel code developer, this was totally useless and I gave up this driver. There are simpler userland alternatives for that. Going further, I think (no flame please ;-) that having the full linux-dvb in kernel space has become a conceptual mistake nowadays. The amount of kernel code should remain as small as possible and limited to hardware device access. A software demux has nothing to do in kernel space. IMHO, there should be a userland API that does this. The kernel drivers should report the capabilities of the hardware devices, such as demux. If the device has demux capabilities, the userland code sends the PID filter to the device. Otherwise, the complete TS is passed in userland and demux is done in the API. Demuxing is just one example, all non-hardware related features of linux-dvb should be moved out of the kernel. This is a common disease of open-source developers who are sometimes too much ego-driven: they want to be part of the small kernel coders community and add features in the kernel for fun. It is a well-known debate about the Linux kernel being to bloated. Anyway, coming back to linux-dvb and Dektec, kernel drivers exist for both, just write userland code to access the one you want. -Thierry -Message d'origine- De : [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] De la part de Andrea Venturi Envoyé : mercredi 3 octobre 2007 15:10 À : linux-dvb Objet : Re: [linux-dvb] DVB API update Manu Abraham wrote: Hi, Simon Hailstone wrote: Hi All, If it sheds any light on the nature of DVB-ASI, there are Linux drivers available ( with source ) for the DekTec ASI adapters here : http://www.dektec.com/Products/LinuxSDK/Downloads/LinuxSDK.zip If someone has the hardware, we can take a go at it. hi, here in Cineca, we are running an open source project called JustDvb-It, it's a DVB DSMCC carousel server for interactive television, you could grab it here: http://www.cineca.tv/labs/mhplab/JustDVb-It%202.0.html as we need to interface broadcaster stuff like multiplexer (with DVB ASI interfaces), we use plenty of these Dektec card like DTA140 and so on.. but for that purpose we found sufficient the driver provided by Dektec. it's a simple character device with some IOCTL.. it should be not a tough task to implement a simple LinuxDvb driver, at least for the inbound card (but there's an outgoing path too..), but is this feature valuable? the best usage i can think of, is the dvbsnoop utility for analysis purposes.. anyway i surely can test this driver, if it will spring out! bye andrea venturi Regards, Manu Best Regards, Simon Hailstone On 16/09/2007, *Wolfgang Wegner* [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: Hi Manu, On Sun, Sep 16, 2007 at 02:17:55AM +0400, Manu Abraham wrote: Please don't remove the CC's. The CC'd people generally don't bother about mails from the ML, probably. sorry, it was definitely not my intention and I hope to include
Re: [linux-dvb] RE : linux-dvb and Dektec [was: DVB API update]
Hi, On Wed, Oct 03, 2007 at 04:42:20PM +0200, Thierry Lelegard wrote: IMHO, the Linux DVB framework serves two main purposes: - Common API for the zillions of DVB-S/C/T adapters - Common frontend for TV watching programs such as Myth et al. Dektec products address the market of professional test lab applications using ASI input/output, QPSK/QAM/OFDM modulators output. They address separate needs, separate usage. it depends. I think there is at least one usage case where one might want to have the DekTec card integrated into the linux-dvb driver framework, which already has been mentioned: us the existing linux-dvb applications with it! Especially dvbsnoop is a very helpful tool for some cases. I definitely want to start another war about which functionality should be in the kernel and which not, but IMHO the usage is not as separate as you claim. Best regards, Wolfgang ___ linux-dvb mailing list linux-dvb@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
