This prevents having to sign-extend on 64-bit systems with 32-bit ints,
such as x86-64. Also fixes crashes on systems where we don't do it and
arguments are not in registers, such as Win64 for all weight functions.

Output packet size should match avctx->block_align. The target output packet
size is 1024 bytes.
Before:
mono   - 1024 samples -> 512 bytes
stereo - 2048 samples -> 2048 bytes
After:
mono   - 2048 samples -> 1024 bytes
stereo - 1024 samples -> 1024 bytes

This will allow parsers to export the duration of the current frame being
output, if known, instead of using AVCodecContext.frame_size.

Signed-off-by: NPaul B Mahol <onemda@gmail.com>
Signed-off-by: NJustin Ruggles <justin.ruggles@gmail.com>

Also, only set bit rate for CBR.

also remove unneeded commented-out full frame data debugging

We now require at least libmp3lame 3.98.3.
lame_encode_buffer_interleaved() still doesn't work for mono, but it does not
"die"; it just expects a stereo interleaved buffer.

it is already set in avcodec_alloc_frame()

This avoids reading any old data in the AVIOContext buffer after
the seek, and indicates to the mpegts demuxer that we've seeked,
avoiding continuity check errors.
Signed-off-by: NMartin Storsjö <martin@martin.st>

Set the pict_type/key_frame properties on the coded picture.

This makes switching to encode2() simpler, because it allows us to know
exactly how large should the output buffer be before we start writing
into it.

Red zone usage is not allowed in the Win64 ABI.

Revert "swscale: update context offsets after removal of AlpMmxFilter."
(commit a95e3fa9)
and
Revert "swscale: Remove some write-only variables related to alpha handling."
(commit 9d03cb9f).

They broke alpha handling - it's the evil inline asm that still uses that
variable, so it's not truely write-only.

Enhance seeking by demuxing until the requested timestamp is
reached within the segment selected by the seek code using the
playlist info.

Some mpegts streams don't have dts set for all packets though,
this seeking method doesn't work well for that case.
Signed-off-by: NMartin Storsjö <martin@martin.st>

Update api so it will compile again.

Signed-off-by: NPaul B Mahol <onemda@gmail.com>
Signed-off-by: NJustin Ruggles <justin.ruggles@gmail.com>