Unsure whether my Motion JPEG video is progressive or interlaced?

[dandove]

I have some video, which was recorded using the movie mode of a Minolta 7HI digital camera purchased in 2003. Mediainfo shows the codec to be Motion JPEG. When I transfer the clips into TMPGenc software, the clip properties indicates progressive scan. I am wondering if this is definitely the case, as I am unable to find confirmation from MediaInfo or any other source. I want to check I have the right setting for the scan, so I can set the encoding option correctly. As I am editing the video, I thought this was the right section to post in but if I am wrong please point me in the right direction. Any help would be appreciated. Thanks.

[manono]

Use your eyes. If you don't see interlacing, then it's not interlaced. Watch using a player you can pause and advance frame-by-frame to check more closely in a section with steady movement. Just make sure that it doesn't have deinterlacing turned on. Most have it on by default.

Can you open it in VDub (or VDub2)? If so, they won't deinterlace it and you'll easily be able to tell if it's progressive or not.

Or, you can post a few seconds here for someone to have a look.

[Bernix]

Manono is right.
I would be surprised if the video is interlaced. From principe of jpeg compression. Mjpeg supports interalcing, but do not see any advantage of it. It is I frame only format, and interlace do compression harder for jpeg. Less effective.
So I belive majority of mjpeg compression is progressive.


Bernix

[jagabo]

MJPEG was one of the most popular codecs for video capture in the early days -- because it was fast, offered different quality levels, and could handle interlaced video. Video compressed with it may be interlaced or progressive. You can open an MJPEG video with VirtualDub and look for comb artifacts. Or post a short sample (a medium speed panning shot is best) here and someone will look at it for you.

[pandy]

MJPEG is not standard and thus interlaced/progressive support depends on each codec implementation. Most of MJPEG codecs works as progressive i.e. interlaced frame (made form both fields) is compressed as progressive frame - this lead to unavoidable artefacts (Gibbs effect) - MJPEG is not the best choice. You may try to encode fields with MJPEG to avoid issues (separate fields and later combine them).

[jagabo]

MJPEG is not the best choice

The OP probably has no choice. It's what his camera gives him.

[pandy]

MJPEG is not the best choice

The OP probably has no choice. It's what his camera gives him.

There is high chance that sensor provide progressive video thus no problem with MJPEG - you and others already advised to OP to check if produced video is progressive or not. IMHO MJPEG don't support alternate and zigzag DCT scan thus i doubt is there serious interlaced MJPG implementations but who knows - every silicone vendor especially for pro use may try to solve this issue on they own way (usually not compatible with other vendors).

[jagabo]

The OPs camera is from 2003. Many still cameras used MJPEG for video in that era.

Here's PicVideo's MJPEG configuration dialog with an interlaced setting:



ffdshow also has an interlaced setting:

[pandy]

The OPs camera is from 2003. Many still cameras used MJPEG for video in that era.

Here's PicVideo's MJPEG configuration dialog with an interlaced setting:

ffdshow also has an interlaced setting:

Once again - MJPG is not standardised - it is ad hoc implemented way to deal with video signal when JPG (or rather DCT) technology (mostly silicone) was available. Provided screen shots do not tell anything about how signal is processed internally - it can be processed as separate fields thus progressive frame with half of vertical resolution and doubled framerate, it can be only flag associated with content, it can be finally proper interlaced processing i.e. interlaced frame, alternate DCT scan type etc. This was my point from begining... MJPEG is suboptimal for interlaced as way how interlaced is processed is large grey (undefined) zone. MPEG-2 I frame is very similar to MJPG but there is clear specification how to deal with interlaced video.

[jagabo]

The OPs camera is from 2003. Many still cameras used MJPEG for video in that era.

Here's PicVideo's MJPEG configuration dialog with an interlaced setting:

ffdshow also has an interlaced setting:

Once again - MJPG is not standardised - it is ad hoc implemented way to deal with video signal when JPG (or rather DCT) technology (mostly silicone) was available. Provided screen shots do not tell anything about how signal is processed internally - it can be processed as separate fields thus progressive frame with half of vertical resolution and doubled framerate, it can be only flag associated with content, it can be finally proper interlaced processing i.e. interlaced frame, alternate DCT scan type etc. This was my point from begining... MJPEG is suboptimal for interlaced as way how interlaced is processed is large grey (undefined) zone. MPEG-2 I frame is very similar to MJPG but there is clear specification how to deal with interlaced video.

The OP isn't making MJPEG video, he already has MJPEG video and is looking at how to deal with it. I suspect his video is progressive. But he needs to verify it.

[dandove]

Many thanks for your replies. I cannot see any combing but I thought I would upload a clip with hopefully the right kind of panning so that somebody with more knowledge of these matters than myself can take a look, if they wouldn't mind, so that I am certain what kind of video I'm dealing with.

[jagabo]

It's progressive. It wouldn't make sense for it to be interlaced at 320x240 and 15 fps. If the camera has the option to shoot larger frames (e.g. 720x480 at 29.97 fps) those might be interlaced.

[dandove]

Thanks very much for that.