Change "Top field first" flag

[geohei]

As far as I understood, an interlaced MPEG-2 file contains a flag called "Top field first". By mistake, I encoded a few MPEG-2 streams with the wrong field setting (bottom instead of top first). Is there a tool which permits to toggle this "Top field first" bit inside the stream?

TIA

[adam]

You can use ReStream, Pulldown.exe, or DVDPatcher. The first two only accept elementary streams (mp2 rathern than mpg) but DVDPatcher should be able to work with an mpg.

[dlawedor]

That is fine to know

[dlawedor]

Can somebody give a short explanation how to use the programs (listed by adam) to change the field order ? Thanx, dlawedor

[geohei]

I looked at the screenshot of DVDPatcher. However I didn't find any option to change the field order. adam, are you sure this is possible with DVDPatcher?

TIA

[adam]

Sorry, I thought DVDPatcher could do it, my mistake.

ReStream and pulldown.exe definitely work though. You will have to demux your mpg, process the video stream, and then remux, but I don't think there is anyway to avoid this process.

If you use restream or pulldown.exe via the gui, its pretty intuitive. In both, just load your source and set a destination then select the field order you want to use. In pulldown it uses odd/even which correlates to top/bottom respectively, and in restream it uses top field first vs. unchecked which of course means bottom field.

[geohei]

I tried both programs now.

TMPEGEnc - Simple De-multiplex
ReStream
TMPEGEnc - Simple Multiplex

The resulting file is identical (checked with a byte-per-byte comparator) to the one from TMPEGEnc with the opposite field order. Hence, it's exactly like I would not have done the mistake with the field order.

pulldown.exe also worked, but the resulting file was not identical, though it had exactly the same size.

Many thanks for your help !!!