Hello all!

(BTW: I've not posted this in software or hardware forums as I don't know if this a software or hardware problem - not sure which one!).

I'm currently trying to video capture some of my old VHS video tapes. However no matter what video capture device I try (or no matter which tape) there always seems to be a problem I'm having - the video capture is dropping frames.

To do this I'm using the latest version of debian (buster). The system I'm using is an older system however it should be able to surely do video captrue. It's an AMD Phenom II x2 555 CPU, 4 GB of RAM, onboard graphics. No hard drive but I'm using a SATA SSD of 55GB.

The capture devices I've tried are PCI and USB based. Right now I'm using a USB device (as both devices seem to have the same frame drop problem). The USB device is a USBTV007 video grabber (Easycap) 1B71:3002 .

I can see the video captured by this device OK with a programmed called QT V4L2 test utility and I can also hear the audio coming into the capture device without problem.

I'm also wanting to capture using lossless (not lossy) audio and video and I am using the following command line to perform the capture:

This works and video and audio are recorded ok. However eventually for some reason I'm getting dropped frames - out of a 48 min video I ended up with 305 dropped frames.

However I'm also seeing this error listed several times while capturing:

The PC I'm using isn't really doing much else apart from running normal KDE. However try as I might I can't find the reason for the frame drops. It seems to happen no matter if I use an older PCI device or the USB device mentioned above and also with any tape.

BTW I can confirm my VHS video recorder I'm using is working; I am capturing via its svideo output (and the machine I'm using even has a TBC which is powered on). Its model number is HR-S7600.

Has anyone experienced problems with frame dropping while doing analog video capture at all? I know this used to be a problem a long time ago with older PCs but largely that really was down to the PC and any I/O being too slow to keep up!

Thanks

ljones

Is that HR-S7600 a JVC? I had a JVC HR-S7500U, which was NTSC, not AFAIK PAL capable. Are your VHS tapes PAL? If NTSC I'd be trying -f 30 instead of -f 25.

i have no clue about the hardware being used.
can't they save the video to a file directly? why do you need ffmpeg?

if not, and you really need to capture an actual video stream, here's a general comment:

• it is transcoding on the fly. is your cpu powerful enough to manage that with your settings?
• you might want to try just dumping the raw data to disc. not sure you even need ffmpeg for that, but in any case, the resulting file will be HUGE.

PS: possibly my ignorance in these matters shows.

It's definately a 7600 btw and PAL compatible and a JVC. All my stuff here is PAL-I (I should have mentioned I am from the UK, oops!). Plays VHS/PAL-I tapes with no problem.

I have found that the files are large but I'm wanting to make sure I preserve the videos at the best quality possible so the large files I'm getting are fine no problem with that. Maybe even an old Phenom II x2 isn't enough?

I do remember back in the late 90s and early 2000s being able to do reasonably good video capture with an old Matrox G400TV although a) that was a hardware based solution; b) it could be made to work in linux, but hasn't seen an update in an eternity; the card itself was based on the old zoran chipset ( the webspage is at http://marvel.sourceforge.net/ ). And I don't think I even have that hardware any more (not sure) plus it is an old AGP based device(!).

I do understand I'm likely to drop a few frames with old tapes but is 305 normal (305/25)? That represents about 12 seconds(!) worth of video -- so unless it is something to do with the CPU just being too slow I'm not sure.

i sense there is a lot of misunderstanding here about how these things work.
capturing a stream from a separate device does not typically involve the graphic card at all.

you should get more familiar with how this thing actually works.

personally, i'd try to just capture the stream directly from /dev/video1 or something liek that.
not saying that that's how it's done, just that that's what i would try first.

if you really capture raw data, the output WILL be too large by any measure, and significant compression is possible with no or imperceptible loss.

and yes, i think any old (10 years or more?) cpu is too weak to do encoding-on-the-fly.

here's a search - suitably the first 2 results are about ubuntu.

>capturing a stream from a separate device does not typically involve the graphic card at all.

Very true although the device I mentioned in my last post (Matrox G400TV) was a graphics card which doubled up as a video capture device as it had the zoran chipset built onto it - which when it worked worked well, but little in the way of support on linux. Although we're talking about something that dates from the late 90s/early 2000s and is long since out of date.

>personally, i'd try to just capture the stream directly from /dev/video1
An intresting idea I have never tried this method. Will have to try it out and see if it works. One small problem though -- that won't include the sound!
Update: That idea didn't work 100% - I ended up with corrupt video x.x

>and yes, i think any old (10 years or more?) cpu is too weak to do encoding-on-the-fly.
Drat! Looks like I'll have to try to upgrade the hardware x.x !

One thing I'm going to try is to see what happens if I install the cpufrequtils package and set the CPU governor to "performance" (/etc/default/cpufrequtils). Don't think that will do anything but worth a go! I didn't have it installed at all.

Update 2: Drat that didn't make any difference. But I did try one other thing -- using the same USB capture device, VHS machine and tape (above) I tried doing about a ~5 min recording. On the Phenom II x2 555 I mentioned above I got around 30 or so frame drops. I tried on my "main" PC which has a AMD FX 6300 6-Core CPU ( a CPU with 'six' appeal, prehaps hehe :-) ) and 32GB RAM again running off a SSD and I got 0 framedrops.

ljones

i still don't understand:
"The USB device is a USBTV007 video grabber"
you have hardware that is specifically built to do what you want, no?
concentrate your searches on making it work- e.g.:
https://linuxtv.org/wiki/index.php/E...BTV007_EasyCAP

Yep it does what I need to do, it is just annoying that I'm getting framedrops although the problem is the same with other devices I've tried. I did get better results with a slightly newer machine (above, AMD FX 6300 6-Core CPU) although I'd need to try it more extensively. Might be just that the CPU and RAM on the machine I'm using is too slow.

ljones

If this may indeed be the problem then you ought to test with a DE or WM with less overhead and bloat than KDE. Have you tried FVWM, I3-WM, IceWM or TWM? (I'd start with IceWM.)

Well to be honest I did kinda think of that one -- I tried using just the command line straight without any GUI but I still got the same problem x.x although that was still "running" KDE but only at the login screen (I just pressed CTRL-ALT-F2 to get a command line without logging into KDE). I have an older SSD here in a SATA to USB converter frame with TDE (trinity desktop) on it maybe that might work?

ljones

TDE, originally forked from KDE3, is very light compared to the KDE Plasmas.