The two checks using eof_reached are testing whether more input can
possibly appear on this filtergraph input. InputFilterPriv.eof is the
more authoritative source for this information.
When an input stream terminates and no frames were successfully decoded,
filtering code will currently configure the filtergraph using demuxer
stream parameters. Use decoder parameters instead, which should be more
reliable. Also, initialize them immediately when an input stream is
bound to a filtergraph input, so that these parameters are always
available (if at all) and filtering code does not need to reach into the
decoder at some arbitrary later point.
When no frames are ever seen by an encoder, encoder flush will do a
last-ditch attempt to configure its source filtergraph in order to at
least get the stream parameters. This involves extracting demuxer
parameters from filtergraph source inputs, which is
* a bad layering violation
* probably unreachable, because decoders are flushed before encoders,
which should call ifilter_send_eof(), which will also set these
parameters; however due to complex control flow it is hard to be
entirely sure this code can never be triggered
Even if this code can actually be reached, it is probably better to
return an error as the comment above it says.
These two functions are a part of a single logical action - determining
which, if any, output stream needs to be processed next. Keeping them
separate is a historical artifact that obscures what is actually being
done.
Currently those are set in different ways depending on whether the
stream is decoded or not, using some values from the decoder if it is.
This is wrong, because there may be arbitrary amount of delay between
input packets and output frames (depending e.g. on the thread count when
frame threading is used).
Always use the path that was previously used only for streamcopy. This
should not cause any issues, because these values are now used only for
streamcopy and discontinuity handling.
This change will allow to decouple discontinuity processing from
decoding and move it to ffmpeg_demux. It also makes the code simpler.
Changes output in fate-cover-art-aiff-id3v2-remux and
fate-cover-art-mp3-id3v2-remux, where attached pictures are now written
in the correct order. This happens because InputStream.dts is no longer
reset to AV_NOPTS_VALUE after decoding, so streamcopy actually sees
valid dts values.
This was added in 380db56928 as a
temporary crutch that is not needed anymore. The only case where this
code can be triggered is the very first frame, for which InputStream.pts
is always equal to 0.
Stop using InputStream.dts for generating missing timestamps for decoded
frames, because it contains pre-decoding timestamps and there may be
arbitrary amount of delay between input packets and output frames (e.g.
dependent on the thread count when frame threading is used). It is also
in AV_TIME_BASE (i.e. microseconds), which may introduce unnecessary
rounding issues.
New code maintains a timebase that is the inverse of the LCM of all the
samplerates seen so far, and thus can accurately represent every audio
sample. This timebase is used to generate missing timestamps after
decoding.
Changes the result of the following FATE tests
* pcm_dvd-16-5.1-96000
* lavf-smjpeg
* adpcm-ima-smjpeg
In all of these the timestamps now better correspond to actual frame
durations.
If input packets have timestamps, they will be propagated to output
frames by the decoder, so at best this block does not do anything.
There can also be an arbitrary amount of delay between packets sent to
the decoder and decoded frames (e.g. due to decoder's intrinsic delay or
frame threading), so deriving any timestamps from packet properties is
wrong.
The previous name is misleading, because the function does not actually
initialize any filters - it creates a new output stream and binds a
filtergraph output to it.
Their only function is checking that encoding was not specified for
data/unknown-type streams, but the check is broken because enc_ctx will
not be created in ost_add() unless a valid encoder can be found.
Add an actually working check for all types for which encoding is not
supported in choose_encoder().
James Almer
Anton Khirnov
Davy Durham