Friday, 2019-05-10

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TD-LinuxI figured out I also need to replug USB after using the tty, but I get test pattern capture now!04:30
TD-Linuxit really doesn't want to sync to 25.175mhz though. it picks 26.68mhz04:37
CarlFKTD-Linux:  what os/distro?04:41
TD-Linuxfedora 3004:41
CarlFKinstead of un/plugging, try rmmod uvcvideo; modprobe uvcvideo04:46
TD-Linuxthat also fixes it04:46
CarlFKand hopefully  this is consistant:  it only gets stuck if you use the tty before uvc.04:47
TD-LinuxAHA I got it to work04:48
TD-Linuxmy output device (OSSC) defaults to HDMI and I forgot to set it to DVI today04:48
CarlFKoh yeah, that.04:48
TD-Linuxit still totally falls over in the BIOS (640x400)04:48
TD-Linuxit's randomly missing hsyncs04:49
TD-Linuxbut this is much better :D04:57
TD-Linuxthere's also a fair bit of digital speckle noise, strangly only on certain grays.05:00
mithroTD-Linux: Look at the debug output around the error rate05:03
mithroTD-Linux: Actually, I wonder what is the lowest frequency the PLL will lock too...05:03
TD-LinuxIt seemed to be 20mhz based on the source code.05:03
TD-Linuxhuh the tty works *after* the uvc stream starts05:04
CarlFKyeah, that tty/uvc bug is weird.05:04
mithroTD-Linux: Yeah, the usb stack needs improvement05:04
TD-Linuxwhere do I see debug error rate?05:04
mithroI started a rewrite but never got to finishing it05:04
mithrodebug input0 on05:04
mithroI think...05:04
TD-Linuxdvisampler1: ph:  58   54   48 // charsync:111 [5 5 5] // WER:  2   3   0 // chansync:1 // res:640x48005:05
mithroTD-Linux: BTW What type of cable are you using to feed the opsis?05:05
TD-Linuxan HDMI cable from the OSSC's output05:05
TD-Linux6 feet05:05
TD-LinuxI can try a shorter, better one05:05
mithroTD-Linux: You should pick up a RedMere cable, it has an internal amplifier which increases the compatibility of the opsis with certain hardware05:06
tpbTitle: Dissecting HDMI - Developing open, FPGA-based capture hardware for conference & user group recording [33C3] - Google Slides (at
mithroTD-Linux: Describes the output of that05:07
TD-Linuxis this an ok cable?
mithroTD-Linux: CarlFK is the expert05:10
TD-Linux(the OSSC is a box that has a video ADC so I can capture analog VGA)05:10
CarlFKTD-Linux: that amazon looks good05:11
TD-Linuxeventually I want to make an ecp5 based board that has half of the OSSC on it and runs hdmi2usb... but it seems easier to get it working with the discrete components first so I don't add more hardware debugging to the mix :)05:12
CarlFKmithro: any idea where the wiki page is that lists things like the atx box I use?05:13
mithroTD-Linux: FYI - rohit did a VGA capture board for the Atlys, there is even a design for the board on a tofe interface05:13
mithroCarlFK: Nope!05:13
mithroCarlFK: Guessing maybe?05:14
tpbTitle: Home · timvideos/HDMI2USB Wiki · GitHub (at
TD-Linuxmithro, oh cool! I'll see if I can find it05:14
tpbTitle: GitHub - timvideos/HDMI2USB-TOFE-VGA: A VGA capture board for use with TOFE-8x compatible boards like the Numato Opsis. (at
TD-LinuxI assume this requires special opsis firmware05:15
mithroCan't recall the state of it...05:15
CarlFKTD-Linux: I don't think said special firmware has been written05:16
mithroCarlFK: correct, but I believe Rohit has all the pieces05:16
mithroSomeone just needs to finish it...05:17
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mithroOh, speak of the devil05:17
mithroHey rohitksingh_work! We were talking about your GSoC project from back in the day!05:17
tpbTitle: Redmere Cables · timvideos/HDMI2USB-numato-opsis-docs Wiki · GitHub (at
mithroCarlFK: I would have never found that page!05:18
mithroTD-Linux: BTW Have you found ?05:19
CarlFKmithro: I'm still wondering there the page of other hardware is05:19
TD-LinuxCarlFK, it would be nice if that wiki page was on this repo instead
tpbTitle: Home · timvideos/HDMI2USB Wiki · GitHub (at
CarlFKI want to order the 6 pin molex? power connectors05:19
TD-Linuxout of curiosity are the redmere cables better because they have better amps than the ones on the opsis board or do they do error correcting magic better than the fpga code05:21
CarlFKmithro: close, but there is a page with where to source the stuff - with part numbers05:21
mithroTD-Linux: The Opsis board doesn't have any amplifiers in it, it relies on the output matching the HDMI spec05:22
mithroI'm pretty sure we could improve the HDMI input detection following a similar path to what bunnie did for the NeTV205:23
TD-Linuxthe ossc drives its hdmi output directly from a IT661305:24
TD-Linuxit's possible that chip is potato05:25
CarlFK'we' (that I know of) don't even try with normal cables.05:25
mithroAbout ~80% of devices work without Redmere cables05:27
TD-Linuxlooks like most programs deal OK with the JPEGs coming out a different resolution than advertised in UVC05:28
TD-Linuxmpv being an exception05:30
mithroTD-Linux: Ever wanted to learn what it's like to program for an 8052? :-P05:31
mithroanyway, heading home now - have a gnight!05:31
TD-Linuxmithro, whitequark has already told me plenty about the fx2 :^)05:31
TD-Linuxit's actually a bit annoying though. ideally I'd like the output res to change automatically but that's forbidden by UVC :(05:32
TD-LinuxI guess I could cause a reset, reappear with a different descriptor, and make sure OBS has enough logic to restart the stream05:33
mithroTD-Linux: porting our UVC firmware to whitequarks new fx2 library would be a good idea05:42
tpbTitle: HDMI2USB-fx2-firmware/uvc.c at fx2-refactor · timvideos/HDMI2USB-fx2-firmware · GitHub (at
tpbTitle: HDMI2USB-fx2-firmware/uvc.h at fx2-refactor · timvideos/HDMI2USB-fx2-firmware · GitHub (at
mithroTD-Linux: if you send mjeg video of resolution A and then resolution B - gstreamer just seems to handle it...05:47
mithroSame with ffmpeg05:47
mithroNo idea what obs uses05:48
mithroThe resolution that UVC negotiates and the UVC mjpeg data stream seem totally independent....05:49
mithroRe-fixing Opsis needing remere cables with litevideo is pretty technical work that requires deep fiddling with ISERDES and IDELAY blocks that only really like Bunnie and _florent_ have the skills to work on05:54
mithroI could /maybe/ do it - but it would be very much pushing the limits of my ability05:55
mithroAlso requires a bunch of time...05:57
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TD-Linuxyeah if that's spartan6 specific tweaking I don't really want to do it either :)08:54
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CarlFKTD-Linux: what are you using OBS for?17:45
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TD-LinuxCarlFK, compositing it with a live video camera19:34
CarlFKhave you tried Voctomix?19:35
CarlFKway less features than obs, but if it can do what you need, maybe easier19:36
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TD-Linuxyou are building for the wrong target22:29
TD-Linuxalso you need to run scripts/build-micropython.sh22:29
CarlFKi don't think futaris is femtoduino22:33
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futarisIRCcloudI have a few quick pointers, in that thread. I'm not femtoduino.23:14
futarisIRCcloudGave - phone autocorrect23:14

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