GSpot media info accuracy?

[ecc]

I wanted to convert a film from PAL to NTSC. I did not notice any interlacing in the PAL source so I opened it in GSpot and it said the PAL image was progressive so I just skipped telecide and just used assumefps(23.976) in my .avs file. GSpot says the resulting file is interlaced/top field first with both frames per second and pictures per second as 23.976 and fields per second as 47.95. I haven't checked the video over rigorously with Virtualdub but I did preview the m2v in VLC with none of the deinterlace filters on and did not notice any interlacing.

I've had this happen before and just ignored it but I just wanted to know if I perhaps did anything wrong or if GSpot is not entirely accurate. With other projects I've only checked after I flagged it for 23.976-29.97 with DGPulldown and that said it was interlaced with 23.976 frames and 29.97 pictures per second in GSpot while Nero identified those as "29.97 Progressive (Telecine)".

[jagabo]

GSpot isn't always entirely accurate, but...

You have two issues: Whether the contents of individual frames is interlaced (whether they contain one picture or two), and whether the frames were encoded as if they were interlaced (MPEG handles interlaced and progressive frames differently internally). It sounds like the source frames were not interlaced but you encoded them as if they were. By encoding progressive frames in interlaced mode you have degraded the image quality unnecessarily.

[ecc]

My fault. I thought that "auto select" in the encoder meant that it would select interlaced or progressive based on the loaded video and the arguments in the avs file but apparent "auto select" means select TFF or BFF.

[ecc]

So GSpot should read I/L (even though its really progressive), 23.976 fps, 29.97 p/ps, and 59.95 fields, right?

[jagabo]

Yes, GSpot calls it interlaced because the final output will be 59.94 interlaced fields per second.