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mpv/audio/decode/dec_audio.h
wm4 0af5335383 Rewrite ordered chapters and timeline stuff
This uses a different method to piece segments together. The old
approach basically changes to a new file (with a new start offset) any
time a segment ends. This meant waiting for audio/video end on segment
end, and then changing to the new segment all at once. It had a very
weird impact on the playback core, and some things (like truly gapless
segment transitions, or frame backstepping) just didn't work.

The new approach adds the demux_timeline pseudo-demuxer, which presents
an uniform packet stream from the many segments. This is pretty similar
to how ordered chapters are implemented everywhere else. It also reminds
of the FFmpeg concat pseudo-demuxer.

The "pure" version of this approach doesn't work though. Segments can
actually have different codec configurations (different extradata), and
subtitles are most likely broken too. (Subtitles have multiple corner
cases which break the pure stream-concatenation approach completely.)

To counter this, we do two things:
- Reinit the decoder with each segment. We go as far as allowing
  concatenating files with completely different codecs for the sake
  of EDL (which also uses the timeline infrastructure). A "lighter"
  approach would try to make use of decoder mechanism to update e.g.
  the extradata, but that seems fragile.
- Clip decoded data to segment boundaries. This is equivalent to
  normal playback core mechanisms like hr-seek, but now the playback
  core doesn't need to care about these things.

These two mechanisms are equivalent to what happened in the old
implementation, except they don't happen in the playback core anymore.
In other words, the playback core is completely relieved from timeline
implementation details. (Which honestly is exactly what I'm trying to
do here. I don't think ordered chapter behavior deserves improvement,
even if it's bad - but I want to get it out from the playback core.)

There is code duplication between audio and video decoder common code.
This is awful and could be shareable - but this will happen later.

Note that the audio path has some code to clip audio frames for the
purpose of codec preroll/gapless handling, but it's not shared as
sharing it would cause more pain than it would help.
2016-02-15 21:04:07 +01:00

63 lines
1.7 KiB
C

/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef MPLAYER_DEC_AUDIO_H
#define MPLAYER_DEC_AUDIO_H
#include "audio/chmap.h"
#include "audio/audio.h"
#include "demux/demux.h"
#include "demux/stheader.h"
struct mp_audio_buffer;
struct mp_decoder_list;
struct dec_audio {
struct mp_log *log;
struct MPOpts *opts;
struct mpv_global *global;
const struct ad_functions *ad_driver;
struct sh_stream *header;
struct mp_codec_params *codec;
char *decoder_desc;
bool try_spdif;
// For free use by the ad_driver
void *priv;
// Strictly internal (dec_audio.c).
double pts; // endpts of previous frame
double start, end;
struct demux_packet *packet;
struct demux_packet *new_segment;
struct mp_audio *current_frame;
int current_state;
};
struct mp_decoder_list *audio_decoder_list(void);
int audio_init_best_codec(struct dec_audio *d_audio);
void audio_uninit(struct dec_audio *d_audio);
void audio_work(struct dec_audio *d_audio);
int audio_get_frame(struct dec_audio *d_audio, struct mp_audio **out_frame);
void audio_reset_decoding(struct dec_audio *d_audio);
#endif /* MPLAYER_DEC_AUDIO_H */