If a packet is not ready on the input selected by ffmpeg,
it will read from another input instead. If that happens
repeatedly, frames will accumulate somewhere later in the
processing to ensure streams synchronization. It can happen
in particular when reading from a slow medium or an
expensive lavfi filter graph.
Make reading from normal demuxers on non-streamed data and
from the lavfi pseudo-device blocking to avoid that.
Should fix trac ticket #3079.
Fixes different behavior to JM and probably several if not all
reference decoders.
We cannot just do this unconditionally as it would ruin AV sync in
some use cases.
Bug-Found-by: BugMaster
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Allows, amongst other things, to override the size guessed
by the sub2video hack.
Note: the -s option could have more or less the same semantic,
but it receives a special treatment by the options system.
Until now, the end_display_time was ignored, making single
packets subtitles (like dvdsub) stay indefinitely.
start_display_time was also ignored, but is it almost always 0.
Normally we discard things prior to the intended start
for stream copy this is not always possible, and its not done by default
this option allows discarding to be enabled
this is primarely usefull when transcoding a video and stream copying an
audio stream.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>