Comments inline On Mon, Dec 22, 2014 at 4:07 PM, Tolga Cakir <tolga@xxxxxxxxx> wrote: > Am 09.05.2014 um 14:38 schrieb Steven Toth: >> >> On Thu, May 8, 2014 at 9:48 PM, Tolga Cakir <tolga@xxxxxxxxx> wrote: >>> >>> Hello everyone! >> >> Hi Tolga! >> >>> Over the past weeks, I've been busy capturing USB packets between the >>> Elgato >>> Game Capture HD and my PC. It's using the MStar MST3367CMK chip, which >>> seems >>> to have proprietary Linux support available only for hardware vendors in >>> form of an SDK. Problem is, that this SDK is strictly kept under an NDA, >>> making it kinda impossible for us to get our hands on. >> >> Thanks for raising the subject. >> >> While your comment is true, it would have been more appropriate to the >> development community to say that it truly uses the Fujitsu USB >> encoder, a fujitsu USB API along with a series of smaller subsystems >> for HDMI receivers and transmitters. Your capture logs indicate >> (largely) interaction with the Fujitsu USB bridge + integral encoder. >> The distinction is important. >> >> We outlined the architecture of the device (along with the brief tear >> down) here: http://www.kernellabs.com/blog/?p=1959 >> >>> So, I got my hands dirty and have found some very good stuff! First of >>> all, >>> in contrast to many sources, the Elgato Game Capture HD outputs >>> compressed >>> video and audio via USB! It's already encoded, so there is no need for >>> reencoding, this will save CPU power. For testing purposes, I've only >>> tried >>> capturing 720p data for now, but this should be more than enough. >> >> Have you posted any source code? I don't see any in the zips or on github. >> >> Paging through a 600MB usb capture to find an occasional comment >> (assuming you have inserted them) doesn't encourage me to contribute. >> >>> Basically, we need to read raw USB traffic, write an MPEG-TS file header, >>> put in the raw USB data and close the file. I'm not super experienced in >>> C / >>> kernel development (especially V4L), but I'll give my best to get this >>> project forward. My next step is getting a prototype working with libusb >>> in >>> userland; after that's done, I'll try porting it over to kernel / V4L >>> >>> Project page can be found here: >>> https://github.com/tolga9009/elgato-gchd >> >> I must be missing something. your repo contains a LICENSE file and >> README. Did you forget to checking a homebrew datasheet or working >> sample source code? >> >>> USB logs and docs: >>> v1.0 as 7zip: https://docs.google.com/file/d/0B29z6-xPIPLEQVBMTWZHbUswYjg >>> v1.0 as rar: https://docs.google.com/file/d/0B29z6-xPIPLEcENMWnh1MklPdTQ >>> v1.0 as zip: https://docs.google.com/file/d/0B29z6-xPIPLEQWtibWk3T3AtVjA >> >> Ahh, thank you for circulating the datasheets and images from our blog >> post, you are most welcome! The internet is a wonderful thing, I'm >> glad you found them useful. >> >>> Is anyone interested in getting involved / taking over? Overall, it seems >>> doable and not too complex. I'd be happy about any help! Also, if you >>> need >>> more information, just ask me. I'll provide you everything I have about >>> this >>> little device. >> >> How about instead of some usb dumps, pictures and pdfs, a working >> program and a description of the device protocol? This would help. >> >> I spent a few days late 2012 with the usb analyzer and brought >> together a primitive collection of personal notes on the API. Sadly >> I'm struggling to locate them currently. From memory, the device has >> an odd protocol which isn't exactly obvious. Its firmware like, not >> i2c based. You don't appear to control the HDMI rx/tx silicon by hand, >> the fijutsu firmware does this via firmware APIs. you would think, >> YAY! firmware API, easy, surprisingly not. A lot of byte guess to be >> done. If you have any significant homebrew documentation on the byte >> sequences that control the device, this would help. >> >> Part of the problem is that the device also streams (with the >> windows/osx drivers I was using) permanently on, making it difficult >> to see the wood from the noise. So, even when you are not 'using it', >> its streaming payload via USB to the host. Urgh. I hope they've fixed >> this. >> >> The device outputs native ISO13818 TS packets which are easily >> playable in VLC as is. I don't even think you need to add a header, >> unless you are electing to create an updated PMT. >> >> I have datasheets and/or source on everything except the fujitsu >> encoder, sorry - I can't share. >> >> Keep going with your project, this should be a fun to follow. libusb >> is easy to work with, you should have the device running in no time. >> >> If you can make the device run at both 720p and 1080i then you should >> find enough variance in the protocol bytes, build that into your app, >> to be useful for some people. >> >> - Steve > > > Hi Steven! Hello Tolga. > > thank you for your hints so far! They really helped me moving forward. 6 > months have passed and I was able to learn more about the device. I have > captured some more USB logs using the OpenVizsla USB 2.0 analyzer, comparing > Windows and Mac drivers side-by-side. There are some findings, I want to > share with you: > > - The device has 5 endpoints, excluding EP0. EP1 and EP4 is used for video / > audio transmission and supports bulk transfers only; EP2 is used for booting > firmwares (which are not flashed onto the device, like FPGAs - so, no brick > chance!); EP5 is used for flashing a firmware onto the device and shouldn't > be touched by us. I have no idea about EP3, as I haven't come across of it > yet. You can find the output of "lsusb -v" here: > https://github.com/tolga9009/elgato-gchd/blob/master/descriptors/lsusb_usb_descriptor > > - Setting up the device is done in several, non-trivial steps. There are 2 > firmwares loaded onto the device (which we were able to transfer onto the > device!). > > - I have come across a bootup script, which was bundled with the Elgato Mac > drivers: > https://drive.google.com/file/d/0B29z6-xPIPLEZTZhSzJiQTVoR3c/view?usp=sharing. > This is a very interesting, documented script. You should definitely take a > look at it. The device seems to be using I2C for configuration. I wasn't > able to translate between I2C and the USB packets so far, but I'm sure it > can be done. Based on my first glance, I don't think the driver was talking directly to the parts via i2c, it was requesting features from the driver (such as "set hdmi mode") and the firmware itself was making that happen. Those are generally a little more difficult to debug, but not impossible. My earlier comment is the best advise I can give you: "If you can make the device run at both 720p and 1080i then you should find enough variance in the protocol bytes, build that into your app, to be useful for some people." ^^^ This is the technique I usually begin with - for any undocumented hardware. > > I'm currently stuck after successfully loading the 2nd firmware onto the > device. That's a point, where things are getting really complicated. I have Ah yes, the joy of complication. Keep at it. > studied and compared the (new) USB capture logs countless hours, but wasn't > able to find anything to move forward. Can you look into this a second time? I'm swamped with a number of other projects and probably won't get a chance to look at this in any detail, but I'd be happy to comment on any specific patterns or control byte sequences that you think may be relevant. > You can find everything in the GitHub repo: > https://github.com/tolga9009/elgato-gchd. By the way: Elgato has improved > alot. The new v2.0 Mac drivers stripped away tons of unnecessary USB > packets. That helps concentrating on the important stuff. great! > > Thank you! No, thank you. - Steve -- Steven Toth - Kernel Labs http://www.kernellabs.com -- 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
