The SRT muxer is reponsible for separating events with two line breaks,
there is no need to add more than necessary. Similarly, other muxers
(such as Matroska) are not supposed to add line breaks at the end of the
payload.
Regression since 6057de19b. The ptr-2 is used to eat the \r\n and add
the position information on the timing line. This can't be done in case
of SubRip where the timing isn't present in the payload.
Note that we can't use yet the side data to transmit the position
information since the encode subtitles API is still using buffer+size
instead AVPacket as input.
Unsurprisingly, if a timing-less subrip decoder is desireable, an
encoder is as well. With this in place, we can move on to remove
the use of the old encoder/decoder with embedded timing and move
all timing handling the (de)muxer where they belong.
Signed-off-by: Philip Langdale <philipl@overt.org>