Amarectv and frame rates

[Traderbam]

Hi, I am having no luck avoiding inserted frames and having poor a/v sync with VirtualDub so tried AmarecTV. First thoughts were that the a/v sync seems to be in a much better place. Media Info shows identical file info when compared to a VDub capture.

Things become strange when I import into Staxrip to deinterlace. The fps value is 25fps for previous captures, but in my Amarec test the fps is 24.887384. The target file fps is 49.7747. Media Info shows the frame rate as 25 so I'm not sure what is causing this. Strangely in my deinterlaced file the audio is out of sync, while it is fine in the original avi.

Is this signifying drops/inserts in my capture? What do I need to look for in the generated log file? DRP=0f is at the end of log.

[lollo]

What do I need to look for in the generated log file? DRP=0f is at the end of log.

Post here the log file, and a sample of your capture

[Traderbam]

Log and sample attached. I cut the sample using LosslessCut so it may change the mediainfo slightly.

Screenshot shows Staxrip view when setting up a deinterlacing job for this segment - somewhat off a 25fps input.

[lollo]

Your capture suffer of many dropped frames and inserted frames. They are all detailed in the log file, which has a weird termination at each line.

An example of dropped frame:

NT=00:04:54.008s(Drop), Total=1
VT=00:04:54.052s(7348f), Cap= 8539f(  0D), Enc= 9.857ms, Siz= 296KB( 36%)KEY, Drp=0, (+)66, (-)1, Buf= 1, o

An example of inserted frame:

NT=00:04:57.810s(7433f), Total=90
VT=00:04:57.856s(7434f), Cap= 8606f(  0D), Enc= 7.950ms, Siz= 302KB( 37%)KEY, Drp=0, (+)90, (-)4, Buf= 2, o

In summary, your log reports 94 inserted frames and 6 dropped frames, which is a lot for a 14 minutes capture.It contains all the infos to check where they happen in time:

VT=00:13:52.534s(20802f), Cap=21966f(  0D), Enc= 2.765ms, Siz= 342KB( 42%)KEY, Drp=0, (+)94, (-)6, Buf= 1, o

You should check your workflow and its set-up. If the tape is not in good condition you need a frameTBC device to handle the inconsistencies in timing. If the tape has serious problems, not even a TBC can fix them.
The fact that you experienced better handling of asynch using AmarecTV with respect to VirtualDub is normal.

However, your capture is not bad in term of "visual quality".

Histogram and Levels:


A simple AviSynth resotration with QTGMC, TemporalDegrain2 and LSFmod improves a little bit the video (I did not adjust levels out of 16-235 range):

comp.mp4

The frame rate looks ok at 25 frames per second to me. I do not use any GUI, so I cannot comment on Staxrip handling of interlaced material.

edit: added img comparison https://imgsli.com/MjA1NTMw

[Traderbam]

Thanks lollo, appreciate you digging into this. I think this really confirms the need for frame TBC, not that I needed convincing. I am concerned though that this would be a tape issue that a TBC won't fix either.

I should have said that this tape is actually a recording that was recorded to VHS from a live TV production. I have quite a bit of material of that type that I'd like to digitise. Perhaps it is totally expected that anything recorded from TV will be really poor quality on the tapes. The majority of content I have though is camcorder tape content that is copied to VHS.

Could there be anything dodgy with my USB Live or would that be more noticeable in the visual quality if there was an issue?

Thanks

[Alwyn]

Do you have a TBC in your VCR or are you using an ES-15 type stabiliser? If not, that would probably contribute to the frame inconsistencies. Notice the flagging/flickering at the top of the frame in the first few seconds; a VCR TBC or ES-15 should straighten that out, given the recording itself looks nice and stable.

Perhaps it is totally expected that anything recorded from TV will be really poor quality on the tapes.

Not at all. I have a lot of video from TV recordings and it's quite OK, even 2nd and 3rd generation is quite watchable. With a bit of a tidy-up, that video looks good to me.

[lollo]

Perhaps it is totally expected that anything recorded from TV will be really poor quality on the tapes.

95% of my tapes are recorded from TV and are not too bad. If you had good reception at that time there should not be a problem. But conditions of the tapes as they are today play a major role.

Could there be anything dodgy with my USB Live

On that sample I did not notice anything weird, apart the high number of dropped/inserted frames. In a good capture they should be 0. 1 or 2 drop/insert over 1 hour capturing is still ok and not noticeable.

Check all the conditions to avoid dropped/inserted frames in your system: disable internet, update and antivirus, background running process, ectc. Do absolutely nothing on the PC while is capturing.

[Traderbam]

Do you have a TBC in your VCR or are you using an ES-15 type stabiliser? If not, that would probably contribute to the frame inconsistencies. Notice the flagging/flickering at the top of the frame in the first few seconds; a VCR TBC or ES-15 should straighten that out, given the recording itself looks nice and stable.

I'm using a Philips VR1000 which has a line TBC. This is a JVC clone similar to some of the recommended VCRs on LS lists. Should I be questioning whether the TBC is working correctly or not?

Check all the conditions to avoid dropped/inserted frames in your system: disable internet, update and antivirus, background running process, ectc. Do absolutely nothing on the PC while is capturing.

I have tried this with different VCRs, different capture computers, different tapes, and when using VirtualDub I always had around 33/34 frames inserted right at the beginning. Amarec doesn't seem to have the initial bulk of inserts but the count is still way too high for my liking. Will try again with disabling more of the background processes.

[Alwyn]

Should I be questioning whether the TBC is working correctly or not?

I'd try another capture of that scene and compare. If the flagging/tearing at the top is worse with the TBC off, then it's working. Either way, you have a conundrum with all those drops and inserts.

[Traderbam]

Interesting update... I had another look at the VR1000 manual around TBC settings and did note this "If you playback a tape recorded under poor TV reception condition, there may be cases where the picture becomes more stable with Digital TBC/NR set to off.

The whole reason I bought a VCR with line TBC was for the TBC and now I'm supposed to turn it off

Sure enough, when I run my test captures of the same segment, the flagging/tearing at the top is present with TBC on, but disappears when TBC is off. Surely this is the opposite of what is expected? Could my TBC on/off light be lit when OFF instead of ON or something daft like that?

For a 60 second clip - TBC ON = 20+ inserted frames, TBC OFF = 0 drops/inserts

[Alwyn]

Don't you hate that!

[Traderbam]

Don't you hate that!

Yes, but it's supposed to be a JVC 7600 clone or similar and am pleased with the picture.

Since it is mentioned in the manual I'm more content to experiment, but I do still wonder if the LED status is in fact correct.

[Traderbam]

Here are some samples from captures of the same segments - apologies for large sizes (2GB) - https://1drv.ms/u/s!AoYVwYm0qHh9lrtVvSjSSA2J-vmAtg?e=FGLGsu

[Alwyn]

I don't have the luxury of an onboard TBC, but I have read a few times that sometimes, things are better with it off. A bit like using an ES-10; only if you need to.

[Alwyn]

Oh hang on! Those TBC-off captures have bad flagging: check out the top right. It's sloping in a lot. With the TBC on, apart from the first few seconds, the right side is straight.

IMO, the TBC is working well. It just can't cope with the very start.

Of course, all that doesn't explain the drops and inserts with the TBC on...

[Traderbam]

Oh hang on! Those TBC-off captures have bad flagging: check out the top right. It's sloping in a lot. With the TBC on, apart from the first few seconds, the right side is straight.

IMO, the TBC is working well. It just can't cope with the very start.

Of course, all that doesn't explain the drops and inserts with the TBC on...

Thanks for having a look. At the start I see DSPC on the VCR which is activated on poor tape conditions so I'd put that down to a source issue. Will try and have a play but sounds like frame TBC may be next step here.

[Alwyn]

I suspect that DSPC is the equivalent of JVC's B.E.S.T. It also come on at the commencement of playing a tape.