About mp4

[Rinzler]

Sorry for maybe a noob question. When transcoding film from .mkv to .ts or .mpg output video can be opened with MPC-РС during transcoding (part of the video that has already been transcoded).
When transcoding film from .mkv to .mp4 I can't open output file with MPC-РС during transcoding. Only when transcoding will be fully completed. Why is it so?

p.s. Sorry for my english.

[Asmodian]

Because the index for mp4 is generated at the end of the file and is not written until the trans-muxing is complete. mp4 can store the index at the start or end of the file but it is only written when muxing is complete.

I assume you meant MPC-HC?

[Rinzler]

Yes, MPC-HC. Thanks a lot for help.