Sorry, did not send it to linux-media@xxxxxxxxxxxxxxxx -------- Original Message -------- Subject: Re: Topro 6800 driver Date: Fri, 06 Mar 2009 22:24:55 +0100 From: Thomas Kaiser <v4l@xxxxxxxxxxxxxxx> To: Anders Blomdell <anders.blomdell@xxxxxxxxxxxxxx> CC: video4linux-list@xxxxxxxxxx References: <49A8661A.4090907@xxxxxxxxxxxxxx> Hello Anders Anders Blomdell wrote:
Hi, I'm trying to write a driver for a webcam based on Topro TP6801/CX0342 (06a2:0003). My first attempt (needs gspca) can be found on:
I own a cam with a TP6810 USB bridge and a CX0342 sensor (this is written on the driver CD).
http://www.control.lth.se/user/andersb/tp6800.c Unfortunately the JPEG images (one example dump is in http://www.control.lth.se/user/andersb/topro_img_dump.txt), seems to be bogus, they start with (data is very similar to windows data): 00000000: 0xff,0xd8,0xff,0xfe,0x28,0x3c,0x01,0xe8,... ... 0000c340: ...,0xf4,0xc0,0xff,0xd9 Anybody who has a good idea of how to find a DQT/Huffman table that works with this image data?
I did some usbsnoops today and see some similar things in the stream as in your trace. Maybe you can comment on my observation? When I stop the capturing, the las 2 Bytes are always 0xff 0xd9 which look like a valid JPEG marker (End of Image) When I search for 0xffd9, I see the following sequence: FF D9 5x FF D8 FF FE 14 1E xx xx xx - 5x is 55 or 5A - the 3 xx are mostly the same, but they change a lot when I cover the lens of the cam. So I think this is some image information (brightness?). This said, i don't think that FF D8 and FF FE are JPEG markers, just a unique Byte pattern to mark the start of a new frame. I guess 5x FF D8 FF FE 14 1E xx xx xx and may be some more bytes is the frame marker. Comments? Thomas -- 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
