Wednesday, 2017-03-01

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krokodilerianmithro: around?00:35
mithrokrokodilerian: Kinda00:36
krokodilerianwould you have time to talk now, or in 8 hours?00:36
mithrokrokodilerian: If you have time now, lets just try and chat now?00:37
krokodilerianso, timvideos/hdmi2usb got accepted in gsoc00:37
mithrokrokodilerian: Yes!00:37
krokodilerianand there seem to be people willing to work on it, i have a meeting with them tomorrow00:38
mithrokrokodilerian: It also looks like FOSDEM did too?00:38
krokodileriani saw
krokodilerianhm, did it?00:38
krokodileriani don't know the plans there00:39
krokodileriani'll check with the guys :)00:39
krokodilerianmy idea is to use the hdmi2usb in the second version of the fosdem boxes, but that's more work for this project than for fosdem, i think00:40
krokodilerianso for example, one thing that's missing is the audio input, right?00:41
mithrokrokodilerian: Well, we have limited developer resources, so if FOSDEM needs something specific then you guys will probably need to help with that development...00:41
krokodilerianyes, that's the reason to look for the gsoc students00:42
krokodilerianor you mean for them to be in the fosdem project while working on this?00:42
mithrokrokodilerian: That is an open question I think?00:43
krokodilerianyes, if it's possible00:43
mithrokrokodilerian: By "audio input" what do you mean exactly?00:43
krokodilerianmithro: currently the hdmi2usb has a driver/usb endpoint that behaves like a camera, with a v4l2 driver, but there's no such thing for audio, afaik00:44
krokodilerianso you can't capture audio with it00:44
mithrokrokodilerian: Correct00:44
krokodilerianso this was one example on what i can try to get people to work on (to submit a proposal, etc.)00:44
krokodilerianand anything else you think is relevant/useful00:45
mithrokrokodilerian: The HDMI2USB hardware has no audio inputs/outputs unless you count the audio embedded in the HDMI streams00:45
krokodilerianbecause fosdem's requirements are pretty close to yours00:45
krokodilerianmithro: yes, exactly, that audio00:45
xfxfkrokodilerian: IIRC paddatrapper is working on solving that problem, but it's still a WIP00:45
krokodilerianmithro: this is the usual way we get the audio, via the camera00:45
xfxfwe just use a small USB sound card with XLR in for now00:46
mithrokrokodilerian: How important is that too you? Do you frequently have people with audio in their presentation?00:46
krokodilerianmithro: hm, we plan to use this for both the camera and the presentation00:46
krokodilerianthere's no point in using two kinds of devices00:46
mithrokrokodilerian: Do you have a block diagram (even if just a scribble on paper) of how you might deploy this?00:46
xfxfmithro: audio in for the camera is super useful, in most situations house sound is fed in via XLR on a prosumer cam00:46
mithrokrokodilerian: Then we can discuss which parts are good / bad ideas :-P00:47
xfxfkrokodilerian: that said, having to use a seperate USB device is a slight inconvenience but it's worked fine for us so far00:47
krokodilerianmithro: gimme 5 minutes :)00:47
krokodileriani have some such stuff for the current setup00:47
krokodilerianand i'll draw a bit00:47
mithrokrokodilerian: Okay!00:51
krokodilerian is the current architecture, but there's too much other detail in it00:52
tpbTitle: video/fosdem-video-2017.pdf at master · FOSDEM/video · GitHub (at
krokodilerianmithro: is somewhat what we have now00:54’s server DNS address could not be found.00:54
krokodilerianmithro: is somewhat what we have now00:55
krokodilerianmithro: is somewhat what i want for the future00:55
mithrokrokodilerian: is okay00:55
tpbTitle: video/fosdem-video-2017.pdf at master · FOSDEM/video · GitHub (at
krokodilerian(sorry, a bit sleepy)00:55
krokodilerianbut, there are bits missing here which i need to add00:56
krokodilerianfor example, our presenter box has a vga input, which gets split, and it then gets into the scaler, which goes in the bmd-encoder00:56
krokodilerianso it's possible (and has happened) that what's on the vga split output (that goes to the beamer) is not the same as what's  on the scaler00:57
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mithrokrokodilerian: Yeah, I would like to see more details of your box's insides00:57
krokodilerianso what i want, as a first thing is to have a programmable open device that can get the video+audio from whatever i plug in it that I can pass on without almost any CPU00:57
krokodilerianmithro: i definitely have that somewhere, or mark had...00:58
mithrokrokodilerian: I'm pretty sure I've seen it somewhere....00:58
mithrokrokodilerian: The cabling diagrams in are also useful it seems00:59
tpbTitle: video/graph at master · FOSDEM/video · GitHub (at
krokodilerianmithro: yes, but they don't show the insides of the box01:00
krokodilerianone way to look at those is like a device that can : take video+audio input, display information about it, send it over the network01:00
mithrokrokodilerian: Couple of quick questions about FOSDEM01:00
mithrokrokodilerian: Is it in the same venue most years?01:00
krokodilerianand in the case of presenter box, can also send a copy of the input to a vga or hdmi por01:01
krokodileriansame venue every year, a university in Brussels01:01
krokodilerian24 rooms01:01
krokodilerian(that have to be streamed and recorded)01:01
krokodilerian(oh, right, the boxes also record everything, for backup)01:01
krokodilerianyes, exactly01:02
mithrokrokodilerian: What is the thing in the bottom left?01:03
krokodilerianmithro: scaler - it has hdmi and vga inputs, and scales the output to a specific resolution and doesn't drop the output signal no matter what01:04
mithrokrokodilerian: So the rooms you use at Brussels are VGA only?01:04
krokodilerianso doesn't break the stream if a laptop gets disconnected01:04
krokodilerianmithro: currently,most of them are vga only, some are hdmi+vga01:04
mithrokrokodilerian: Do you have the details about that scaler somewhere?01:04
krokodilerianbut that's changing, and it's not easy to ask people to  always bring vga laptops01:04
mithrokrokodilerian: How comfortable would you be with asking people to bring HDMI laptops?01:06
krokodilerianmithro: it's LENKENG LKV391MINI, , the only site that still has them01:06
tpbTitle: - LENKENG LKV391MINI (at
krokodilerianmithro: we won't, we need to support both hdmi and vga for the time being01:06
mithrokrokodilerian: You only support VGA at the moment?01:07
krokodilerianmithro: this year we had ~10 hdmi-to-vga converters for specific cases01:07
krokodilerianbut yes, we fully support just vga now, and it sucks01:07
mithrokrokodilerian: Would you be okay with the opposite? VGA to HDMI?01:07
krokodilerianmithro: but i'd really prefer it we didn't need any converters01:08
krokodilerianmithro: and there seems to be a 2port vga module for the opsis, where one is input and one is output01:08
mithrokrokodilerian: It's a pass thru device01:09
mithrokrokodilerian: You have no control over the VGA output on that board01:09
mithro(IE You can't send the HDMI inputs out the VGA)01:09
mithroIt does work if nothing is connected to the output though01:09
krokodilerianmithro: so i can input vga, but the output is not really supported atm (or ever)?01:10
krokodilerianif needed, we can live with a few hdmi-to-vga converters, and according to the university, they're working on replacing that everywhere01:11
mithrokrokodilerian: We have had good success with using HDMI->VGA convertors on the output of the Opsis board01:11
mithroWe have had mixed success with VGA->HDMI converters on the Opsis inputs01:12
mithrokrokodilerian: How many of the existing parts do you want to reuse and what type of budget do you have?01:12
krokodilerianmithro: and there's no code written for the vga daughterboard, right?01:12
mithrokrokodilerian: There is a bunch of code written for it, but nothing currently in a usable state01:13
krokodilerianmithro: budget-wise - i have no good idea, but we can probably buy 50-60 opsis boards01:13
mithrokrokodilerian: at what price are you expecting to be getting the Opsis boards?01:13
krokodilerian400eu? no idea, i need to run this by some people in the staff, but should be doable, as it's basically the same price as the bmd encoder01:14
mithrokrokodilerian: Okay01:14
krokodilerianand this is for 2019 (as i really don't think we'll have the time to do it in a year)01:15
mithrokrokodilerian: You mentioned capture inside that box - is the BannanaPi or the BM box doing that?01:16
krokodilerianmithro: the bmd thing (it's connected over USB to the banana, which just takes the stream and encapsulates it in mpeg-ts in UDP)01:16
krokodilerianmithro: it's this thing:
tpbTitle: Blackmagic Design: H.264 Pro Recorder (at
mithrokrokodilerian: how does the bmd thing save the result?01:17
krokodilerianmithro: there's a piece of software called bmd-streamer, which talks to it and just fetches the h.264 stream, from there we pipe it into ffmpeg and a local file01:18
krokodilerianthe reason we use this device is that the bitrate is configurable and we don't need to do any encoding ourselves, so the banana pi suffices01:19
mithrokrokodilerian: Ahh, so capture is running on the BPi and it blackmagic board should really be called a "XXX to USB converter device"01:19
krokodilerianmithro: yes, exactly :)01:19
mithroSo the Opsis board will only do MJPEG, it doesn't do H26401:19
krokodilerianmithro: i know, and i think someone asked that on the ccc talk01:20
krokodilerianand it should be possible to get that or any other not-insanely-big codec on it01:20
mithrokrokodilerian: It is unlikely we'll get anything like H264 any time soon either01:20
mithrokrokodilerian: Do you guys do confidence screens or similar?01:21
krokodilerianmithro: what's a confidence screen?01:21
mithrokrokodilerian: A screen in front of the presenter which shows them what is currently on the screen behind them01:23
mithrokrokodilerian: It suppose to stop them from turning around and looking at the presentation screen all the time01:23
krokodilerianmithro: on fosdem - no. there's something on the display of the box, but it's really small, and mostly for debugging01:23
mithrokrokodilerian: And help when their laptop doesn't do that itself01:24
krokodilerian(the setup is minimalistic, as everything is multiplied 24 times)01:24
mithrokrokodilerian: One solution CarlFK has been doing is kind of like your box, but it is a monitor which gets deployed at the front of the room with all the capture stuff mounted on the back of it using a VESA mount01:25
mithrokrokodilerian: Getting HDMI audio working is definitely something which has the potential to be a GSoC project01:26
krokodilerianmithro: and how do you get the captured stream to the video mixer, via something else?01:26
krokodilerianmithro: and h.264 ?01:27
krokodilerian(or theora, or whatever)01:27
krokodileriani know the codec is hard, but is it possible to port it from something else?01:27
mithrokrokodilerian: No, a small Python script streams the MJPEG video to voctomix over Gigabit Ethernet01:27
krokodilerianmithro: or are there licensing issues?01:27
mithrokrokodilerian: Which BanannaPi boards do you have?01:28
krokodilerianas for mjpeg, if it's below 20mbps, it might be possible to use it for streaming, but we won't be able to record it, i think, the SSDs in the boxes are 64gb01:29
mithrokrokodilerian: The MJPEG is roughly ~300megabits/second -- we just record the output of voctomix in our setup01:30
krokodilerianmithro: - this oke, afaik01:30
tpbTitle: Banana Pi - A Highend Single-Board Computer: Banana Pi (at
mithro(about ~30 megabytes/second)01:30
krokodilerianmithro: we record in voctomix, but also on the boxes, as the network might/will fail01:31
krokodilerianand for 300mbps per box/600mbps per room the network people will hate me :)01:31
krokodilerian(or just kill me)01:31
mithrokrokodilerian: You don't run voctomix in the room?01:32
krokodilerianmithro: no, voctomixes run in a central place, this year we had 24 laptops, as the primary plan for encoding servers failed, next year we'll go with servers01:32
krokodilerianmithro: i wrote a crude and simple web control for vocto, for the people who wanted to use it, otherwise it was PiP01:33
mithroWe always run an in-room network01:33
krokodilerianwe have an in-room network, but everything goes out to a central location (or few)01:35
krokodilerianthe multicast helps a lot with debugging, too01:35
krokodilerian( explains the architecture)01:38
tpbTitle: video/ at master · FOSDEM/video · GitHub (at
krokodilerianmithro: about the codec, is it possible to do anything, or are there licensing issues which nobody wants to touch?01:39
mithrokrokodilerian: Its non-trivial amount of work, IE a good engineer multiple months of work01:39
krokodilerianmithro: so, to recap, currently the audio is an interesting project, and maybe the vga, what else would be doable in gsoc?01:42
krokodilerianmithro: anyway, i really need to go to bed, can you drop me a line what should i propose to the students to propose as projects, and i'll talk to them tomorrow01:54
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CarlFKmithro: the /topic here needs fixing.  mainly add
mithroCarlFK: Have you tried fixing it?02:23
CarlFK(08:24:27 PM) You're not a channel operator02:32
CarlFKhere is my try: /topic  GSoC:   IRC logs:  Mailing lists -   Website - http://code.timvideos.us02:33
tpbTitle: Google Groups (at
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CarlFK   links to gst-swtich  - can that be removed?02:39
CarlFKeventstreamer was pretty tied to DVswitch - so I think that can go too02:39
tpbTitle: GitHub - timvideos/website: The website (at
CarlFKmithro: should I remove references to gst-switch or replace with a link to vocto?02:42
mithroCarlFK: replace with vocto02:52
tpbTitle: Programmers are confessing their coding sins to protest a broken job interview process | The Outline (at
xfxffrom that article: “Hello, my name is Tim. I’m a lead at Google with over 30 years coding experience and I need to look up how to get length of a python string,”04:27
xfxfis that you?  did you forget len()? :P04:27
xfxf(micolous_ said it was you)04:28
mithroI didn't start coding at age 3 :-P04:35
xfxfi started in basic at age 4, and then pascal when 6 or 7... which begs the question of what the hell happened :P05:09
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mithroxfxf: ping?05:46
mithroxfxf: Do you want to add HDMI2USB control software and/or HDMI2USBd improvements to the GSoC ideas page?05:48
xfxfah, sure, can do.  is that from the GSoC admin thing?05:48
mithroxfxf: Anyone can do that, it's just GitHub05:49
tpbTitle: Issues · timvideos/getting-started · GitHub (at
xfxfright, so link back to the actual related issue on the right repo?05:50
xfxfi'll add to my TODO, won't do now05:50
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mithroClick new and follow the template05:50
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mithrotumbleweed: Do you want to take another look at ?06:49
tpbTitle: Add --reset-gateware by mithro · Pull Request #54 · timvideos/HDMI2USB-mode-switch · GitHub (at
mithroHi ssk132806:55
ssk1328mithro: Hi07:03
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mithrossk1328: I just replied to your reply with some questions07:06
ssk1328mithro: I will get back to you with the replies by later tonight07:07
mithrossk1328: Thanks!07:07
ssk1328mithro: WIll have to do a lot of catching up on those things07:07
mithrossk1328: No worries07:07
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krokodilerianmithro: morning08:33
mithrokrokodilerian: morning08:34
krokodilerianmithro: so, audio and vga for proposals ?08:44
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