avformat: Add fifo pseudo-muxer

Signed-off-by: Jan Sebechlebsky <sebechlebskyjan@gmail.com>
Signed-off-by: Marton Balint <cus@passwd.hu>

1 files changed, 95 insertions, 0 deletions

diff --git a/doc/muxers.texi b/doc/muxers.texi
index 2e95c6f432..2548aeb4d0 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -1440,6 +1440,101 @@ Specify whether to remove all fragments when finished. Default 0 (do not remove)
 
 @end table
 
+@section fifo
+
+The fifo pseudo-muxer allows the separation of encoding and muxing by using
+first-in-first-out queue and running the actual muxer in a separate thread. This
+is especially useful in combination with the @ref{tee} muxer and can be used to
+send data to several destinations with different reliability/writing speed/latency.
+
+API users should be aware that callback functions (interrupt_callback,
+io_open and io_close) used within its AVFormatContext must be thread-safe.
+
+The behavior of the fifo muxer if the queue fills up or if the output fails is
+selectable,
+
+@itemize @bullet
+
+@item
+output can be transparently restarted with configurable delay between retries
+based on real time or time of the processed stream.
+
+@item
+encoding can be blocked during temporary failure, or continue transparently
+dropping packets in case fifo queue fills up.
+
+@end itemize
+
+@table @option
+
+@item fifo_format
+Specify the format name. Useful if it cannot be guessed from the
+output name suffix.
+
+@item queue_size
+Specify size of the queue (number of packets). Default value is 60.
+
+@item format_opts
+Specify format options for the underlying muxer. Muxer options can be specified
+as a list of @var{key}=@var{value} pairs separated by ':'.
+
+@item drop_pkts_on_overflow @var{bool}
+If set to 1 (true), in case the fifo queue fills up, packets will be dropped
+rather than blocking the encoder. This allows to continue streaming without
+delaying the input, at the cost of ommiting part of the stream. By default
+this option is set to 0 (false), so in such cases the encoder will be blocked
+until the muxer processes some of the packets and none of them is lost.
+
+@item attempt_recovery @var{bool}
+If failure occurs, attempt to recover the output. This is especially useful
+when used with network output, allows to restart streaming transparently.
+By default this option is set to 0 (false).
+
+@item max_recovery_attempts
+Sets maximum number of successive unsuccessful recovery attempts after which
+the output fails permanently. By default this option is set to 0 (unlimited).
+
+@item recovery_wait_time @var{duration}
+Waiting time before the next recovery attempt after previous unsuccessful
+recovery attempt. Default value is 5 seconds.
+
+@item recovery_wait_streamtime @var{bool}
+If set to 0 (false), the real time is used when waiting for the recovery
+attempt (i.e. the recovery will be attempted after at least
+recovery_wait_time seconds).
+If set to 1 (true), the time of the processed stream is taken into account
+instead (i.e. the recovery will be attempted after at least @var{recovery_wait_time}
+seconds of the stream is omitted).
+By default, this option is set to 0 (false).
+
+@item recover_any_error @var{bool}
+If set to 1 (true), recovery will be attempted regardless of type of the error
+causing the failure. By default this option is set to 0 (false) and in case of
+certain (usually permanent) errors the recovery is not attempted even when
+@var{attempt_recovery} is set to 1.
+
+@item restart_with_keyframe @var{bool}
+Specify whether to wait for the keyframe after recovering from
+queue overflow or failure. This option is set to 0 (false) by default.
+
+@end table
+
+@subsection Examples
+
+@itemize
+
+@item
+Stream something to rtmp server, continue processing the stream at real-time
+rate even in case of temporary failure (network outage) and attempt to recover
+streaming every second indefinitely.
+@example
+ffmpeg -re -i ... -c:v libx264 -c:a aac -f fifo -fifo_format flv -map 0:v -map 0:a
+  -drop_pkts_on_overflow 1 -attempt_recovery 1 -recovery_wait_time 1 rtmp://example.com/live/stream_name
+@end example
+
+@end itemize
+
+@anchor{tee}
 @section tee
 
 The tee muxer can be used to write the same data to several files or any