Use the revision just before libspeexdsp split

Using lowest PTS or DTS is a bad idea, as lower video packets are sent
ahead of pts, and most audio tracks are sending packets near to pts.
So we had audio packets coming late, with a lower pts, and corrupted
our PCR as we take the lowest pts among tracks.
We can't also guess the full tracks rolls, so updating after a full
roll instead of each packet is useless.
Send time is a reliable base time.

Offsets pts & duration

Reads keyframe flag from payload extensions.
Some formats like DVR-MS ships keyframe info into
payload extensions and not as packet flag. Why make things simple ?

already microseconds

Sub-Payloads must have their pts computed from deltapts.

Use pts as track time, and then for pcr.

It was unused since VLC started using automake, 11 years ago.

Tested with http://www.martinunderwood.f9.co.uk/mallard.wtv

On windows the latter uses the console API under the hood.

This gives VLC output the same format on Linux and on Windows (tested with wine),
rather than printing the pointer ID at the end of the line.

Pad with 0s, remove 0x prefix

This application is incompatible with Mavericks, and it is superseded by the mechanisms provided
within the UI itself.

Also update the readme to reflect this change.

Close #9522

Ref #9522

There is no point building FFI for its own sake since VLC does not use
FFI directly on any platform.

This reverts commit c2e4f7c6.