Remuxer example does not work

[Luni-4]

The remuxer example does not work:

• It doesn't open the input file correctly through AccReader
• It doesn't mux the packets entirely and panics after a while

[Luni-4]

If the remuxer works with your last changes, @FreezyLemon, can I close this issue?

[FreezyLemon]

It doesn't work yet. The header is now fixed, but there are apparently more problems with it. I'll take another look at it

[FreezyLemon]

The demuxing part looks correct, something goes wrong during serialization. I guess serialization needs a bit more attention then