The record file was written from the stream thread. As a consequence,
any blocking I/O to write the file delayed the decoder.
For maximum performance even when recording is enabled, send
(refcounted) packets to a separate recording thread.
To packetize the H.264 raw stream, av_parser_parse2() (called by
av_read_frame()) knows that it has received a full frame only after it
has received some data for the next frame. As a consequence, the client
always waited until the next frame before sending the current frame to
the decoder!
On the device side, we know packets boundaries. To reduce latency,
make the device always transmit the "frame meta" to packetize the stream
manually (it was already implemented to send PTS, but only enabled on
recording).
On the client side, replace av_read_frame() by manual packetizing and
parsing.
<https://stackoverflow.com/questions/50682518/replacing-av-read-frame-to-reduce-delay>
<https://trac.ffmpeg.org/ticket/3354>
Limit source code to 80 chars, and declare functions return type and
modifiers on a separate line.
This allows to avoid very long lines, and all function names are
aligned.
(We do this on VLC, and I like it.)
The extradata buffer is owned by libav, so it must be allocated with
av_malloc(), not SDL_malloc().
This fixes a crash on Windows during avformat_free_context().
Implement recording to Matroska files.
The format to use is determined by the option -F/--record-format if set,
or by the file extension (".mp4" or ".mkv").
Some containers force their own time base. For example, matroska
overwrite time_base to (AVRational) {1, 1000}.
Therefore, rescale our packet timestamps to the output stream time base.
Suggested-by: Steve Lhomme <robux4@ycbcr.xyz>
AVStream.codec has been deprecated in favor of AVStream.codecpar.
Due to the FFmpeg/Libav split, this happened in two separate versions:
- 57.33.100 for FFmpeg
- 57.5.0 for Libav
