Dots on light backgrounds, 8mm video tapes

[Encode8489]

Hi! Sorry for the newbie question, I'm a millennial so I know almost nothing about analog video.

I'm trying to digitalize some old family video tapes, but when playing them I noticed there are a lot of moving dots, especially visible on white and light backgrounds.

Do you think it's the tapes that are deteriorating, or the camcorder, or maybe I need to clean the tape head?
I noticed that, in some attempts to digitize them, a few years ago, the dots were less visible.

I attach some pictures.
Thanks

[dellsam34]

Where is the white dots, I don't see anything.

[Alwyn]

I suggest you do a short capture of one of the problem areas and post the raw capture file here using the "Upload files/Manage Attachments" feature. They can be up to 500mb. Then we'll be able to see the moving dots.

[Bwaak]

What are you compressing with? What is the bitrate? A short sample would help.

Your picture is slanted to the left, you don't mind it? I wonder does it wave left-right when playing.

Also, judging by the diagonals, it looks like you have the video deinterlaced to just a single field.

[Alwyn]

...

[Encode8489]

At the end, I tried to plug the camcorder into the TV, and I noticed there weren't the dots there, so it was an issue with my old Avermedia capture card.
I therefore bought a Hauppauge USB-Live2, and with it the dots don't appear.
I attach two capture, with the Avermedia, and with the Hauppauge.

Actually, the Avermedia capture was done a few years ago, so I'm not sure about the settings I used. Probably I just used the Avermedia software with the default settings.

The Hauppauge instead was done with ffmpeg:

ffmpeg -f alsa -thread_queue_size 16384 -i hw:2,0 -f v4l2 -thread_queue_size 16384 -i /dev/video0 -filter_complex "[0:a]channelsplit=channel_layout=stereo:channels=FL[left];[1:v]copy[video]" -map "[left]" -map "[video]" -acodec pcm_s16le -vcodec libx264 -crf 0 -preset faster -qp 0 -flags +ilme+ildct -x264-params interlaced=1 -t 3900 output.mkv

My plan is to capture and archive them with a near-original quality (I actually read that libx264 with -crf 0 -qp 0 is lossless, but I'm not sure, as the output file looks a bit too small to me, it's about 30 GB per hour).

I then want to create a deinterlaced compressed copy, to keep on my media server for home streaming, and for sharing with others.

I'm doing some tests for ffmpeg (I then plan to use something else, maybe Avisynth with QTGMC?), but I see some artifacts in the final output, I'm not sure if they are deinterlacing artifacts, or if they are some "interferences" (sorry, I'm not sure if is the proper term) present in the original capture, that get amplified by the deinterlace filter.

ffmpeg -i output.mkv -vf yadif=1:0 -vcodec libx264 -acodec aac -crf 10 -preset veryfast output.mp4

What do you guys think? Can I improve something?

Thanks!

[Sharc]

Where is the white dots, I don't see anything.

He probably means all the grey dots in the pictures of his post#1 which look like mosquitos.

[Sharc]

What do you guys think? Can I improve something?

Just as hints:
- Maybe consider using a lossles codec like huffyuv, utvideo, lagarith, or ffv1 instead of lossless x264. The x264 lossless capture is fine but there is some reluctance about using it for archiving due to compatibility concerns.

- The stream of the capture is wrongly flagged as BFF, but it is actually TFF

- You may want to try a better deinterlacer like QTGMC (with optimized settings) or BWDIF instead of yadif.

- You could shift the luma (brightness) about 16 steps down to fit it better into the 16.....235 limited TV range and avoid blown out brights (e.g. sky and rocks in the elephants scene, or the rock at the end of the Rhino scene).
And perhaps raise the gamma a little if you want to elevate the darks (shadows). A matter of personal preference

- If the filesize of the re-encodes matters you may consider using a higher crf and slower preset for x264 for same quality.

- You should flag the DAR as 4:3 (or you have to force the player to play it as 4:3).

[Samson_stages]

The heads and other components of your VCR or camcorder can accumulate dirt, dust, or residue over time. This buildup can cause video artifacts, including moving dots. But it'll be great if you can post a clearer picture, focusing on the problem (white dots). Can't see the dots.

[Encode8489]

- Maybe consider using a lossles codec like huffyuv, utvideo, lagarith, or ffv1 instead of lossless x264. The x264 lossless capture is fine but there is some reluctance about using it for archiving due to compatibility concerns.

I need to do some experiments; I didn't use one of those because I thought they would take up too much disk space.

- The stream of the capture is wrongly flagged as BFF, but it is actually TFF

Where do you see BFF? I see TFF with mediainfo, but I guess is flagged wrong somewhere, because yadif with auto selection was selecting wrong...

- You may want to try a better deinterlacer like QTGMC (with optimized settings) or BWDIF instead of yadif.

Yes, I'm going to try QTGMC, I just used yadif to do some tests because I'm more confident with ffmpeg. I just wanted to ensure the capture wasn't breaking the interlace.

- You should flag the DAR as 4:3 (or you have to force the player to play it as 4:3).

Just discovered that DAR and SAR are not the same... I'm a real newbie. I'm going to fix it.

edit: what I'm supposed to do with the left and right black borders? I'm reading somewhere that they should be cropped, to have the correct aspect ratio... is this true? And what about the top border and the bottom head switching noise?

[Encode8489]

The heads and other components of your VCR or camcorder can accumulate dirt, dust, or residue over time. This buildup can cause video artifacts, including moving dots. But it'll be great if you can post a clearer picture, focusing on the problem (white dots). Can't see the dots.

I actually solve the dots issue, by changing capture card (I'm now using the Hauppauge USB-Live2).

Anyway, you can see them well in the sky, here a cropped picture of the issue with the Avermedia, and the clear capture with the Hauppauge:

[Sharc]

- The stream of the capture is wrongly flagged as BFF, but it is actually TFF

Where do you see BFF? I see TFF with mediainfo, but I guess is flagged wrong somewhere, because yadif with auto selection was selecting wrong...

I am talking about the file hauppauge_original.mkv.
MediaInfo reports it like

Scan type : MBAFF 
Scan type, store method : Interleaved fields 
Scan order : Bottom Field First

But stepping through the separated fields reveals that the video is in fact TFF, so it is flagged wrongly.
It is always highly recommended to verify the field order of interlaced video manually rather than just trust the tools or flags.

[Encode8489]

- The stream of the capture is wrongly flagged as BFF, but it is actually TFF

Where do you see BFF? I see TFF with mediainfo, but I guess is flagged wrong somewhere, because yadif with auto selection was selecting wrong...

I am talking about the file hauppauge_original.mkv.
MediaInfo reports it like

Scan type : MBAFF 
Scan type, store method : Interleaved fields 
Scan order : Bottom Field First

But stepping through the separated fields reveals that the video is in fact TFF, so it is flagged wrongly.
It is always highly recommended to verify the field order of interlaced video manually rather than just trust the tools or flags.

You're right, I think ffmpeg made something nasty when I extracted the 60 seconds sample from the full 1 hour capture. With the original file I see this:

Scan type                                : MBAFF
Scan type, store method                  : Interleaved fields
Scan order                               : Top Field First