libavformat/matroskaenc: Add WebM DASH support

WebM DASH specification [1] requires the Clusters and Cues to be output in a
specific way. Adding a flag to matroskaenc that will enable support for
creating WebM/Mkv files conforming to the WebM DASH specification.

[1] http://wiki.webmproject.org/adaptive-streaming/webm-dash-specification

Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
maintainers: adding myself as a maintainer to webm dash

adding myself as a maintainer to webm dash (part of matroskaenc.c)

Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
x86: hpeldsp: kill hpeldsp_mmx.c

before:
1987 decicycles in 8_x2, 262121 runs, 23 skips

after:
1902 decicycles in 8_x2, 262112 runs, 32 skips

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
x86: hpeldsp: mark _xy2 versions as approximate

Currently, only the mmx version is bitexact, the others (mmxext and
3dnow) are not, in spite of their naming.

Therefore, make their name more obvious. Also restore a comment that
was removed in 71155d7b.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
x86: hpeldsp: avg_pixels_xy2 for mmx2&3dnow

This is a port of the inline assembly of the mmx version to use the
pavg(us|)b instruction.

        8    16
mmx   1498  4355
mmx2  1242  3509

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Support raw dvdsub palette as stored on normal dvd's

This is how the palette is stored on dvd's. Currently
only xbmc passes the palette information to libavcodec
this way.
Check return value of avio_seek and avoid modifying state if it fails

The code still modifies state if the timestamp is not found. Not
sure exactly how to avoid that.
asf hacks
if av_read_packet returns AVERROR_IO, we are done. ffmpeg's codecs might or might not handle returning any completed demuxed packets correctly
added: Ticket #7187, TV Teletext support for DVB EBU Teletext streams
Don't accept mpegts PMT that isn't current
Don't reparse PMT unless it's version has changed
Read PID timestamps as well as PCR timestamps to find location in mpegts stream
Get stream durations using read_timestamp
changed: allow 4 second skew between streams in mov before attempting to seek
fixed: memleak in mpegts demuxer on some malformed (??) mpegts files with too large pes packets

at-visions sample file brokenStream.mpg
Speed up mpegts av_find_stream_info
dxva-h264 Fix dxva playback of streams that don't start with an I-Frame.
add public version of ff_read_frame_flush

We need this since we sometimes seek on the
input stream behind ffmpeg's back. After this
all data need to be flushed completely.