USB HDMI Capture

Edwin_Perez · March 22, 2025, 12:47pm

Most of those USB Capture devices even though they have a blue plug are really USB 2.0... they are fake USB 3.0.

Here is a screenshot of my card that Claims to be 3.0 and has a blue Cable....

Howesey2k · March 22, 2025, 1:47pm

Thanks @Rice The framefate dropped from 60 to 20fps on an i7 nuc running linux. It was in a usb 3/ lightning port when it was working at 60fps. tried a in a blue usb 3.0 and drops to 20 fps and stops working too.

bnhf · March 22, 2025, 2:11pm

I think you mean Thunderbolt.

Howesey2k · March 22, 2025, 2:27pm

Thanks yes I did mean that

Rice · March 22, 2025, 3:52pm

Mabey it’s a Linux limitation thing then. I accidentally plugged it into a usb2.0 on the back of my motherboard and I got 9fps max. It wouldn’t work in channels until it was back on 3.0. Ymmv

Howesey2k · March 23, 2025, 1:29pm

@tmm1 Any joy in stopping it from spinning after a successful stream? I thought maybe make the script disconnect from the HDMI dongle when a stream closes. Like a software version of pulling the usb out and back in

Rice · March 24, 2025, 4:33pm

@tmm1
Is there anything you can do about these errors in the logs? I have hundreds of thousands of these lines when the capture is active making it impossible to find anything in the logs. 100-150 of these lines a second.


2025/03/24 11:27:50.801386 [HLS] ffmpeg: capture-usb-hdmi:  PTS 1252804028406, next:533312 invalid dropping st:0
2025/03/24 11:27:50.802936 [HLS] ffmpeg: capture-usb-hdmi:  DTS 1252804045070, next:549978 st:0 invalid dropping
2025/03/24 11:27:50.802975 [HLS] ffmpeg: capture-usb-hdmi:  PTS 1252804045070, next:549978 invalid dropping st:0
2025/03/24 11:27:50.815313 [HLS] ffmpeg: capture-usb-hdmi:  DTS 1252804061741, next:566644 st:0 invalid dropping
2025/03/24 11:27:50.815373 [HLS] ffmpeg: capture-usb-hdmi:  PTS 1252804061741, next:566644 invalid dropping st:0
2025/03/24 11:27:50.836848 [HLS] ffmpeg: capture-usb-hdmi:  DTS 1252804078397, next:583310 st:0 invalid dropping
2025/03/24 11:27:50.836856 [HLS] ffmpeg: capture-usb-hdmi:  PTS 1252804078397, next:583310 invalid dropping st:0
2025/03/24 11:27:50.858475 [HLS] ffmpeg: capture-usb-hdmi:  DTS 1252804095061, next:599976 st:0 invalid dropping
2025/03/24 11:27:50.858509 [HLS] ffmpeg: capture-usb-hdmi:  PTS 1252804095061, next:599976 invalid dropping st:0
2025/03/24 11:27:50.880197 [HLS] ffmpeg: capture-usb-hdmi:  DTS 1252804111730, next:616642 st:0 invalid dropping
2025/03/24 11:27:50.880230 [HLS] ffmpeg: capture-usb-hdmi:  PTS 1252804111730, next:616642 invalid dropping st:0

Rice · March 24, 2025, 5:19pm

Thank you!!

Howesey2k · March 25, 2025, 5:51pm

Thank you again for getting this to work on Linux. The only issue I am facing now is an audio video syncing issue. Is there anything that can be done to improve it? It's not horrendous but noticeable Thank you again for your hard work.

Howesey2k · March 28, 2025, 10:12pm

Hi @tmm1 I found this about ffmpeg. Might this help my syncing issues?

Correct FFmpeg Sync Audio to Video That is Too Fast or Slow
You can easily do this by using the -async parameter of FFmpeg, which, as per the documentation "Stretches/squeezes" enables the sound stream to match the timestamps. The parameter takes a numeric value for the samples per second to fix the issue.

ffmpeg -async 25 -i input.mpg -r 25

Attempt gradually expanding the - async value until the sound and video are in sync.

Many thanks

hancox · March 30, 2025, 10:29am

turtletank:

MacOS 15.3.1

So MacOS considers these devices to be cameras and applies strict Privacy & Security restrictions to them.

I did some research this morning and as far as I can tell it is just not possible to access a camera from a process that is running as a LaunchAgent. It seems this was an intentional decision made by Apple and to be fair it makes sense.

With a standard installation of Channels DVR, ffmpeg will just hang as it never receives any video input.

For testing purposes I was able to work around this by running Channels DVR manually.
launchctl unload ~/Library/LaunchAgents/com.getchannels.dvr.plist
cd ~/Library/Application\ Support/ChannelsDVR/data
../latest/channels-dvr
and the following to run Channels normally when you are finished
launchctl load ~/Library/LaunchAgents/com.getchannels.dvr.plist
@tmm1 have you found a good workaround for this?

Still scratching my head at this - @tmm1 are you running your mac DVR manually? It's just so odd that yours worked straight away on post 1, and everyone else has the same issue as the quoted post.

TerryD · April 5, 2025, 8:21pm

@tmm1 I'm getting a strange error on the latest pre-release. Hoping you can point me in the right direction.

2025/04/05 13:11:40.798882 [TNR] Opened connection to M3U-USBHDMICapture for ch11634 USB HDMI Capture
2025/04/05 13:11:40.798882 [HLS] Starting live stream for channel 11634 from 192.168.50.149
2025/04/05 13:11:41.872075 [HLS] ffmpeg: capture-usb-hdmi:  [aist#0:1/pcm_s16le @ 00000211575f9e00] Guessed Channel Layout: stereo
2025/04/05 13:11:41.872075 [HLS] ffmpeg: capture-usb-hdmi:  [vost#0:0/h264_nvenc @ 00000211575eaec0] -enc_time_base -1 is deprecated, use -enc_timebase demux
2025/04/05 13:11:41.975603 [HLS] ffmpeg: capture-usb-hdmi:  [aost#0:1/aac @ 000002115c82e740] -enc_time_base -1 is deprecated, use -enc_timebase demux
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:  Failed to negotiate pixel format between 'graph 0 input from stream 0:0' and 'auto_scale_0':
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      graph 0 input from stream 0:0 (buffer)
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      ↓ yuyv422
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      ↑ yuyv422
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      auto_scale_0 (scale)
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      ↓ yuv420p, yuyv422, rgb24 (+183 more)
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      ⚠️ hwupload needed ⚠️
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      ↑ cuda
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      Parsed_scale_cuda_0 (scale_cuda) [requires cuda]
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      ↓ cuda
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      ↑ yuv420p, nv12, p010le (+13 more)
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      format
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      ↓ yuv420p, nv12, p010le (+13 more)
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      ↑ yuv420p, yuyv422, rgb24 (+227 more)
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:      out_0_0 (buffersink)
2025/04/05 13:11:41.977689 [HLS] ffmpeg: capture-usb-hdmi:  Impossible to convert between the formats supported by the filter 'graph 0 input from stream 0:0' and the filter 'auto_scale_0'
2025/04/05 13:11:41.978220 [HLS] ffmpeg: capture-usb-hdmi:  [vf#0:0 @ 00000211579ba800] Error reinitializing filters!
2025/04/05 13:11:41.978220 [HLS] ffmpeg: capture-usb-hdmi:  Failed to inject frame into filter network: Function not implemented
2025/04/05 13:11:41.978220 [HLS] ffmpeg: capture-usb-hdmi:  Error while filtering: Function not implemented
2025/04/05 13:11:41.979813 [HLS] ffmpeg: capture-usb-hdmi:  [out#0/mpegts @ 00000211576f3b40] Nothing was written into output file, because at least one of its streams received no packets.
2025/04/05 13:11:42.036382 [ERR] Error during stream M3U-USBHDMICapture ch11634 USB HDMI Capture: exit status 0xffffffd8
2025/04/05 13:11:42.036382 [TNR] Closed connection to M3U-USBHDMICapture for ch11634 USB HDMI Capture
2025/04/05 13:11:42.036382 [HLS] ffmpeg: ch11634-dANY-ip192.168.50.149-remux:  [in#0/mpegts @ 000002a6e1343480] could not find codec parameters
2025/04/05 13:11:42.036382 [HLS] ffmpeg: ch11634-dANY-ip192.168.50.149-remux:  Error opening input file -.
2025/04/05 13:11:42.036382 [HLS] ffmpeg: ch11634-dANY-ip192.168.50.149-remux:  Error opening input files: End of file
2025/04/05 13:11:42.041941 [HLS] Stopping transcoder session ch11634-dANY-ip192.168.50.149 (out=0s finished=true first_seq=0 last_seq=-1)
2025/04/05 13:11:42.042625 [ERR] Probe cancelled for live stream after 1.24321s and 0 bytes

this worked with pre-release 2025.03.01.2019
Changed from video_size=1920x1080 to video_size=1280x720 resolved the issue.

hancox · May 10, 2025, 1:09pm

Hey @turtletank - any chance that one of these would possibly bypass this camera classification? (even if the price stings)

Otherwise, we're kind of stuck on mac until @tmm1 works some magic here.

chDVRuser · May 10, 2025, 5:39pm

There are some less expensive ($15.99) versions available

$13.99

But I don't think they'll do HDMI to USB C capture, only USB C to HDMI output.

MBDVRHD · July 17, 2025, 5:13pm

I have the same devices in my list and they don't seem to be working. Is this still working for you?

user3162 · July 17, 2025, 6:29pm

I switched to using OBS Studio, it's free and works great. Just select USB Audio and USB Video capture inputs.
After a recording, I import into Channels.

hancox · August 2, 2025, 10:53am

Half wondering if using the new native containers come September might help this camera hardware layer.

Otherwise this solution seems pretty DOA on Mac, oddly

turtletank · August 2, 2025, 2:58pm

If the native containers allow hardware passthrough and could be started automatically at boot it might offer a solution on the Mac. But I'm doubtful.

I pretty much gave up on this. I also think it is dead on the Mac. Apple took intentional steps to block camera access to background processes and I can't imagine that is going to change as it's actually a good policy for most users.

Channels DVR works well when run via launchd and moving it to a Login Item or something to enable this would be a downgrade.

It is a great idea, it just didn't pan out on the Mac. I really like my M4 Mac mini so I'm just gonna stick to external HDMI encoder hardware for the time being.

hancox · October 31, 2025, 11:20am

@tmm1 Can we take another crack at this on Mac, given MacOS 26 is now live/somewhat bedded in?

ESPN+ going DRM has me scrambling.

MapGuy11 · November 20, 2025, 11:15pm

Does anyone know how to manually pass that you want mjpeg and not yuv2? My capture card supports both for certain resolutions and I can't find a way to pass the specific codec through channels. I have a feeling it's not using mjpeg since when I do 60 fps it throws an I/O error but 30fps (even though it looks very choppy) will work.