Video capture from USB capture device

I don't know if anyone on this forum has used video capture devices in Linux, but I thought I would ask.

I have a StarTech SVID2USB2 (USB ID eb1a:2821) that I want to use in Lubuntu 18.04 (I upgraded since my last posts in this forum - no more Athlon XP). Unfortunately, this is one of the unknown devices in the em28xx driver.

https://kernel.readthedocs.io/en/latest/media/v4l-drivers/em28xx-cardlist.html

I opened the capture device and found that it uses the same board as the Plextor device reviewed here (Google translated from Russian):

https://translate.google.com/translate?hl=en&sl=ru&tl=en&u=https%3A%2F%2Fwww.ixbt.com%2Fdivideo%2Fplextor.shtml

There are multiple cards in the first link that use the same chips, which makes me think the implementation is different between cards (possibly firmware - if I remember right, the chip that review skipped over is an EEPROM). Forcing the driver to initialize the device as card 9 was one suggestion I found, and it didn't work. The only software that gave any output at all was OBS, and it had distorted video and no audio. I've discovered that the card appears as a USB audio device, but Audacity in Windows records silence unless video was captured first. (Note that I was testing capture software in a virtual machine on my main desktop instead of the real computer.)

Once again, I don't know if anyone on this forum has done this, but maybe someone can refer me to a more relevant support forum. This is the only thing I need Windows for on my laptop (and Windows 7 runs a lot worse than Linux does on a Core i3-2330M with 4GB of RAM).

Edited by lti, 16 June 2019 - 11:32 PM.

Don't know the first thing about this 'area of expertise'.....but you may get more joy with these guys:-

https://www.avforums.com/

Mike.

Edited by Mike_Walsh, 17 June 2019 - 10:32 AM.

I was able to capture video in the virtual machine by enabling USB 3.0 support in VirtualBox (I was using USB 2.0 because this is a USB 2.0 capture device), but there is still no sound. I can try it on the real computer later. It's really late right now.

The constant search for Linux drivers that will never see the light of day, combined to the fact that the devices are proprietary, is bound to cause lots of frustration and wasted time.  The easiest path is to use devices that already stream standard protocols over Ethernet, and for example, use ffmpeg to record their output.

I don't have sound on a real computer either. I think the problem is either drivers (as you mentioned) or the way Linux handles the audio input. The Windows driver seems to be universal, but the Linux em28xx driver isn't. In Windows, I don't have to use the software included with the card to enable audio. Video captured in VirtualDub or OBS has sound.

Replacing the capture device is an option. The video quality from this one isn't very good. A replacement will probably use USB 2.0 like this one, and it needs to have an audio input. This laptop only has a microphone input instead of a line-in jack.

Warmly recommended!

https://www.silicondust.com/hdhomerun/

I should have made it more clear that I'm just capturing video from composite video sources.

I did find a muting setting, but it was not accessible until I switched the modprobe option from card=9 to card=31 (USBGear VD204 - same chips as the StarTech device). OBS now records audio, but the pitch is shifted. The audio stays in sync through the capture, so it isn't using the wrong sample rate and playing at the incorrect speed. Audacity records correctly, so it seems like a problem with OBS. I don't really feel like messing with it much due to the poor video quality from this device, but Windows is painful to use on this combination of CPU, RAM, and hard drive.

I listened to my test file more closely and noticed that the audio was really playing too slow and skipping ahead periodically to stay in sync. Setting the default sample rate in PulseAudio to 48kHz solved that, but the audio still drops out or stutters randomly through the capture.

I just wanted to add that update in case someone else has the same problem.

Since I'm reviving a five-year-old thread, I will admit that I haven't done much with newer distros. I did get something captured in FFmpeg under Lubuntu 22.04, but the video was a little "soft" and the audio was ridiculously out of sync (around 1.5 seconds). Maybe differences in the audio system over the years will help. The EM2820 chip in this device is so old that I doubt that there have been any driver changes. I remember that I tried VideoView as Mike_Walsh suggested here, but it could only capture from the laptop's webcam. I've also switched computers because the USB ports started going flaky on the laptop I was using back then (mice still work, but video captures were garbage and file transfers to USB storage only went at 10MB/s). I'm now on a ThinkPad P53 (which is also the only computer I've tried where this capture device works under Windows 10), but I will probably do some testing on my desktop or a VM as well.

I haven't used anything Arch-based at all, but I'll look at EndeavourOS. I'm doing a little distro-hopping right now.

A more modern capture device is also an option. I would like something that can capture VHS tapes (people seem to like the IO-Data GV-USB2, but I don't know what chipset it's based on), but as a last resort, I could try to fix the USB ports on that old laptop (and upgrade the hard drive if I'm successful) since it still dual-boots with Windows 7.

Edited by lti, 01 June 2024 - 01:25 PM.

Since I've never used Arch before, will it have alternate drivers that replace the em28xx driver (which I'm assuming is in the kernel)?

I don't see any drivers besides the kernel em28xx driver, but maybe I'm not using the right search terms. However, what I captured with OBS five years ago and FFmpeg recently gives me hope that it's a software problem, not a driver problem. It seems like there's a lot of Linux capture software for UVC devices, but not for older stuff like this (or the CX231xx chips in the Hauppauge USB-Live2, Diamond VC500, and Elgato Video Capture, which are all still in production). I'll dig through the AUR to see what kind of capture software pops up (and GUI-based configuration tools - v4l2ucp looks helpful).

I've been thinking that I should upgrade my capture device anyway. I have primarily been capturing S-Video, but being able to capture component or HDMI would be nice. It will have to be USB (UVC for Linux compatibility, obviously) for use with my laptop (or a network streaming box that I can also capture in Linux). It's hard to find anything through the endless sea of cheap garbage "USB 3.0" devices that are really USB 2.0 with a blue connector or the MS2109 dongles that have broken audio and fail extremely quickly. The other extreme is gaming capture devices with high refresh rate and HDR support, which I don't need.