mxf: Introduce ff_mxf_get_samples_per_frame

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
mxf: Set audio packets pts

Extrapolate audio timestamps based on the number of samples demuxed.

Deal with some MXF nastiness involving fractional number of
samples per EditUnit when seeking (the specs handwave this away).

Further fixes from Tomas Härdin.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
mxf: Handle identification metadata

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
mxf: Parse random index pack

Get the last partition offset and use it when footer partition
offset is missing.

Footer partition may not be present and even if present footer
partition offset may not be set in any partition except last one.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
mxf: Return meaningful errors
dxva2: Increase maximum number of slices for mpeg2

Some content requires an higher number of slices in order to
render properly.

Rise the number to 1024 and warn if ever it exceeds.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>