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path: root/player/playloop.c
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/*
 * 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/>.
 */

#include <stddef.h>
#include <stdbool.h>
#include <inttypes.h>
#include <math.h>
#include <assert.h>

#include "config.h"
#include "mpv_talloc.h"

#include "common/msg.h"
#include "options/options.h"
#include "common/common.h"
#include "common/encode.h"
#include "common/recorder.h"
#include "options/m_config.h"
#include "options/m_property.h"
#include "common/playlist.h"
#include "input/input.h"

#include "misc/dispatch.h"
#include "osdep/terminal.h"
#include "osdep/timer.h"

#include "audio/decode/dec_audio.h"
#include "audio/filter/af.h"
#include "audio/out/ao.h"
#include "demux/demux.h"
#include "stream/stream.h"
#include "sub/osd.h"
#include "video/filter/vf.h"
#include "video/decode/dec_video.h"
#include "video/out/vo.h"

#include "core.h"
#include "client.h"
#include "command.h"

// Wait until mp_wakeup_core() is called, since the last time
// mp_wait_events() was called.
void mp_wait_events(struct MPContext *mpctx)
{
    bool sleeping = mpctx->sleeptime > 0;
    if (sleeping)
        MP_STATS(mpctx, "start sleep");

    mpctx->in_dispatch = true;

    mp_dispatch_queue_process(mpctx->dispatch, mpctx->sleeptime);

    mpctx->in_dispatch = false;
    mpctx->sleeptime = INFINITY;

    if (sleeping)
        MP_STATS(mpctx, "end sleep");
}

// Set the timeout used when the playloop goes to sleep. This means the
// playloop will re-run as soon as the timeout elapses (or earlier).
// mp_set_timeout(c, 0) is essentially equivalent to mp_wakeup_core(c).
void mp_set_timeout(struct MPContext *mpctx, double sleeptime)
{
    mpctx->sleeptime = MPMIN(mpctx->sleeptime, sleeptime);

    // Can't adjust timeout if called from mp_dispatch_queue_process().
    if (mpctx->in_dispatch && isfinite(sleeptime))
        mp_wakeup_core(mpctx);
}

// Cause the playloop to run. This can be called from any thread. If called
// from within the playloop itself, it will be run immediately again, instead
// of going to sleep in the next mp_wait_events().
void mp_wakeup_core(struct MPContext *mpctx)
{
    mp_dispatch_interrupt(mpctx->dispatch);
}

// Opaque callback variant of mp_wakeup_core().
void mp_wakeup_core_cb(void *ctx)
{
    struct MPContext *mpctx = ctx;
    mp_wakeup_core(mpctx);
}

// Process any queued input, whether it's user input, or requests from client
// API threads. This also resets the "wakeup" flag used with mp_wait_events().
void mp_process_input(struct MPContext *mpctx)
{
    for (;;) {
        mp_cmd_t *cmd = mp_input_read_cmd(mpctx->input);
        if (!cmd)
            break;
        run_command(mpctx, cmd, NULL);
        mp_cmd_free(cmd);
    }
    mp_set_timeout(mpctx, mp_input_get_delay(mpctx->input));
}

double get_relative_time(struct MPContext *mpctx)
{
    int64_t new_time = mp_time_us();
    int64_t delta = new_time - mpctx->last_time;
    mpctx->last_time = new_time;
    return delta * 0.000001;
}

void update_core_idle_state(struct MPContext *mpctx)
{
    bool eof = mpctx->video_status == STATUS_EOF &&
               mpctx->audio_status == STATUS_EOF;
    bool active = !mpctx->paused && mpctx->restart_complete && mpctx->playing &&
                  mpctx->in_playloop && !eof;

    if (mpctx->playback_active != active) {
        mpctx->playback_active = active;

        update_screensaver_state(mpctx);

        mp_notify(mpctx, MP_EVENT_CORE_IDLE, NULL);
    }
}

// The value passed here is the new value for mpctx->opts->pause
void set_pause_state(struct MPContext *mpctx, bool user_pause)
{
    struct MPOpts *opts = mpctx->opts;
    bool send_update = false;

    if (opts->pause != user_pause)
        send_update = true;
    opts->pause = user_pause;

    bool internal_paused = opts->pause || mpctx->paused_for_cache;
    if (internal_paused != mpctx->paused) {
        mpctx->paused = internal_paused;
        send_update = true;

        if (mpctx->ao && mpctx->ao_chain) {
            if (internal_paused) {
                ao_pause(mpctx->ao);
            } else {
                ao_resume(mpctx->ao);
            }
        }

        if (mpctx->video_out)
            vo_set_paused(mpctx->video_out, internal_paused);

        mpctx->osd_function = 0;
        mpctx->osd_force_update = true;

        mp_wakeup_core(mpctx);

        if (internal_paused) {
            mpctx->step_frames = 0;
            mpctx->time_frame -= get_relative_time(mpctx);
        } else {
            (void)get_relative_time(mpctx); // ignore time that passed during pause
        }
    }

    update_core_idle_state(mpctx);

    if (send_update)
        mp_notify(mpctx, opts->pause ? MPV_EVENT_PAUSE : MPV_EVENT_UNPAUSE, 0);
}

void update_internal_pause_state(struct MPContext *mpctx)
{
    set_pause_state(mpctx, mpctx->opts->pause);
}

void update_screensaver_state(struct MPContext *mpctx)
{
    if (!mpctx->video_out)
        return;

    bool saver_state = !mpctx->playback_active || !mpctx->opts->stop_screensaver;
    vo_control_async(mpctx->video_out, saver_state ? VOCTRL_RESTORE_SCREENSAVER
                                                   : VOCTRL_KILL_SCREENSAVER, NULL);
}

void add_step_frame(struct MPContext *mpctx, int dir)
{
    if (!mpctx->vo_chain)
        return;
    if (dir > 0) {
        mpctx->step_frames += 1;
        set_pause_state(mpctx, false);
    } else if (dir < 0) {
        if (!mpctx->hrseek_active) {
            queue_seek(mpctx, MPSEEK_BACKSTEP, 0, MPSEEK_VERY_EXACT, 0);
            set_pause_state(mpctx, true);
        }
    }
}

// Clear some playback-related fields on file loading or after seeks.
void reset_playback_state(struct MPContext *mpctx)
{
    if (mpctx->lavfi)
        lavfi_seek_reset(mpctx->lavfi);

    for (int n = 0; n < mpctx->num_tracks; n++) {
        if (mpctx->tracks[n]->d_video)
            video_reset(mpctx->tracks[n]->d_video);
        if (mpctx->tracks[n]->d_audio)
            audio_reset_decoding(mpctx->tracks[n]->d_audio);
    }

    reset_video_state(mpctx);
    reset_audio_state(mpctx);
    reset_subtitle_state(mpctx);

    mpctx->hrseek_active = false;
    mpctx->hrseek_framedrop = false;
    mpctx->hrseek_lastframe = false;
    mpctx->hrseek_backstep = false;
    mpctx->playback_pts = MP_NOPTS_VALUE;
    mpctx->last_seek_pts = MP_NOPTS_VALUE;
    mpctx->cache_wait_time = 0;
    mpctx->step_frames = 0;
    mpctx->ab_loop_clip = true;
    mpctx->restart_complete = false;

#if HAVE_ENCODING
    encode_lavc_discontinuity(mpctx->encode_lavc_ctx);
#endif

    update_core_idle_state(mpctx);
}

static void mp_seek(MPContext *mpctx, struct seek_params seek)
{
    struct MPOpts *opts = mpctx->opts;

    if (!mpctx->demuxer || seek.type == MPSEEK_NONE || seek.amount == MP_NOPTS_VALUE)
        return;

    if (!mpctx->demuxer->seekable) {
        MP_ERR(mpctx, "Cannot seek in this file.\n");
        MP_ERR(mpctx, "You can forcibly enable it with '--force-seekable=yes'.\n");
        return;
    }

    bool hr_seek_very_exact = seek.exact == MPSEEK_VERY_EXACT;
    double current_time = get_current_time(mpctx);
    if (current_time == MP_NOPTS_VALUE && seek.type == MPSEEK_RELATIVE)
        return;
    if (current_time == MP_NOPTS_VALUE)
        current_time = 0;
    double seek_pts = MP_NOPTS_VALUE;
    int demux_flags = 0;

    switch (seek.type) {
    case MPSEEK_ABSOLUTE:
        seek_pts = seek.amount;
        break;
    case MPSEEK_BACKSTEP:
        seek_pts = current_time;
        hr_seek_very_exact = true;
        break;
    case MPSEEK_RELATIVE:
        demux_flags = seek.amount > 0 ? SEEK_FORWARD : SEEK_BACKWARD;
        seek_pts = current_time + seek.amount;
        break;
    case MPSEEK_FACTOR: ;
        double len = get_time_length(mpctx);
        if (len >= 0)
            seek_pts = seek.amount * len;
        demux_flags = SEEK_BACKWARD;
        break;
    default: abort();
    }

    double demux_pts = seek_pts;

    bool hr_seek = opts->correct_pts && seek.exact != MPSEEK_KEYFRAME &&
                 ((opts->hr_seek == 0 && seek.type == MPSEEK_ABSOLUTE) ||
                  opts->hr_seek > 0 || seek.exact >= MPSEEK_EXACT) &&
                 seek_pts != MP_NOPTS_VALUE;

    if (seek.type == MPSEEK_FACTOR || seek.amount < 0 ||
        (seek.type == MPSEEK_ABSOLUTE && seek.amount < mpctx->last_chapter_pts))
        mpctx->last_chapter_seek = -2;

    // Under certain circumstances, prefer SEEK_FACTOR.
    if (seek.type == MPSEEK_FACTOR && !hr_seek &&
        (mpctx->demuxer->ts_resets_possible || seek_pts == MP_NOPTS_VALUE))
    {
        demux_pts = seek.amount;
        demux_flags |= SEEK_FACTOR;
    }

    if (hr_seek) {
        double hr_seek_offset = opts->hr_seek_demuxer_offset;
        // Always try to compensate for possibly bad demuxers in "special"
        // situations where we need more robustness from the hr-seek code, even
        // if the user doesn't use --hr-seek-demuxer-offset.
        // The value is arbitrary, but should be "good enough" in most situations.
        if (hr_seek_very_exact)
            hr_seek_offset = MPMAX(hr_seek_offset, 0.5); // arbitrary
        for (int n = 0; n < mpctx->num_tracks; n++) {
            double offset = 0;
            if (!mpctx->tracks[n]->is_external)
                offset += get_track_seek_offset(mpctx, mpctx->tracks[n]);
            hr_seek_offset = MPMAX(hr_seek_offset, -offset);
        }
        demux_pts -= hr_seek_offset;
        demux_flags = (demux_flags | SEEK_HR | SEEK_BACKWARD) & ~SEEK_FORWARD;
    }

    demux_seek(mpctx->demuxer, demux_pts, demux_flags);

    // Seek external, extra files too:
    for (int t = 0; t < mpctx->num_tracks; t++) {
        struct track *track = mpctx->tracks[t];
        if (track->selected && track->is_external && track->demuxer) {
            double main_new_pos = demux_pts;
            if (!hr_seek || track->is_external)
                main_new_pos += get_track_seek_offset(mpctx, track);
            if (demux_flags & SEEK_FACTOR)
                main_new_pos = seek_pts;
            demux_seek(track->demuxer, main_new_pos, 0);
        }
    }

    if (!(seek.flags & MPSEEK_FLAG_NOFLUSH))
        clear_audio_output_buffers(mpctx);

    reset_playback_state(mpctx);
    if (mpctx->recorder)
        mp_recorder_mark_discontinuity(mpctx->recorder);

    /* Use the target time as "current position" for further relative
     * seeks etc until a new video frame has been decoded */
    mpctx->last_seek_pts = seek_pts;

    if (hr_seek) {
        mpctx->hrseek_active = true;
        mpctx->hrseek_framedrop = !hr_seek_very_exact && opts->hr_seek_framedrop;
        mpctx->hrseek_backstep = seek.type == MPSEEK_BACKSTEP;
        mpctx->hrseek_pts = seek_pts;

        MP_VERBOSE(mpctx, "hr-seek, skipping to %f%s%s\n", mpctx->hrseek_pts,
                   mpctx->hrseek_framedrop ? "" : " (no framedrop)",
                   mpctx->hrseek_backstep ? " (backstep)" : "");
    }

    if (mpctx->stop_play == AT_END_OF_FILE)
        mpctx->stop_play = KEEP_PLAYING;

    mpctx->start_timestamp = mp_time_sec();
    mp_wakeup_core(mpctx);

    mp_notify(mpctx, MPV_EVENT_SEEK, NULL);
    mp_notify(mpctx, MPV_EVENT_TICK, NULL);

    mpctx->audio_allow_second_chance_seek =
        !hr_seek && !(demux_flags & SEEK_FORWARD);

    mpctx->ab_loop_clip = mpctx->last_seek_pts < opts->ab_loop[1];
}

// This combines consecutive seek requests.
void queue_seek(struct MPContext *mpctx, enum seek_type type, double amount,
                enum seek_precision exact, int flags)
{
    struct seek_params *seek = &mpctx->seek;

    mp_wakeup_core(mpctx);

    if (mpctx->stop_play == AT_END_OF_FILE)
        mpctx->stop_play = KEEP_PLAYING;

    switch (type) {
    case MPSEEK_RELATIVE:
        seek->flags |= flags;
        if (seek->type == MPSEEK_FACTOR)
            return;  // Well... not common enough to bother doing better
        seek->amount += amount;
        seek->exact = MPMAX(seek->exact, exact);
        if (seek->type == MPSEEK_NONE)
            seek->exact = exact;
        if (seek->type == MPSEEK_ABSOLUTE)
            return;
        seek->type = MPSEEK_RELATIVE;
        return;
    case MPSEEK_ABSOLUTE:
    case MPSEEK_FACTOR:
    case MPSEEK_BACKSTEP:
        *seek = (struct seek_params) {
            .type = type,
            .amount = amount,
            .exact = exact,
            .flags = flags,
        };
        return;
    case MPSEEK_NONE:
        *seek = (struct seek_params){ 0 };
        return;
    }
    abort();
}

void execute_queued_seek(struct MPContext *mpctx)
{
    if (mpctx->seek.type) {
        // Let explicitly imprecise seeks cancel precise seeks:
        if (mpctx->hrseek_active && mpctx->seek.exact == MPSEEK_KEYFRAME)
            mpctx->start_timestamp = -1e9;
        /* If the user seeks continuously (keeps arrow key down)
         * try to finish showing a frame from one location before doing
         * another seek (which could lead to unchanging display). */
        bool delay = mpctx->seek.flags & MPSEEK_FLAG_DELAY;
        if (delay && mpctx->video_status < STATUS_PLAYING &&
            mp_time_sec() - mpctx->start_timestamp < 0.3)
            return;
        mp_seek(mpctx, mpctx->seek);
        mpctx->seek = (struct seek_params){0};
    }
}

// -1 if unknown
double get_time_length(struct MPContext *mpctx)
{
    struct demuxer *demuxer = mpctx->demuxer;
    return demuxer ? demuxer->duration : -1;
}

double get_current_time(struct MPContext *mpctx)
{
    struct demuxer *demuxer = mpctx->demuxer;
    if (demuxer) {
        if (mpctx->playback_pts != MP_NOPTS_VALUE)
            return mpctx->playback_pts;
        if (mpctx->last_seek_pts != MP_NOPTS_VALUE)
            return mpctx->last_seek_pts;
    }
    return MP_NOPTS_VALUE;
}

double get_playback_time(struct MPContext *mpctx)
{
    double cur = get_current_time(mpctx);
    if (cur == MP_NOPTS_VALUE)
        return cur;
    // During seeking, the time corresponds to the last seek time - apply some
    // cosmetics to it.
    if (mpctx->playback_pts == MP_NOPTS_VALUE) {
        double length = get_time_length(mpctx);
        if (length >= 0)
            cur = MPCLAMP(cur, 0, length);
    }
    return cur;
}

// Return playback position in 0.0-1.0 ratio, or -1 if unknown.
double get_current_pos_ratio(struct MPContext *mpctx, bool use_range)
{
    struct demuxer *demuxer = mpctx->demuxer;
    if (!demuxer)
        return -1;
    double ans = -1;
    double start = 0;
    double len = get_time_length(mpctx);
    if (use_range) {
        double startpos = rel_time_to_abs(mpctx, mpctx->opts->play_start);
        double endpos = get_play_end_pts(mpctx);
        if (endpos == MP_NOPTS_VALUE || endpos > MPMAX(0, len))
            endpos = MPMAX(0, len);
        if (startpos == MP_NOPTS_VALUE || startpos < 0)
            startpos = 0;
        if (endpos < startpos)
            endpos = startpos;
        start = startpos;
        len = endpos - startpos;
    }
    double pos = get_current_time(mpctx);
    if (len > 0)
        ans = MPCLAMP((pos - start) / len, 0, 1);
    if (ans < 0 || demuxer->ts_resets_possible) {
        int64_t size;
        if (demux_stream_control(demuxer, STREAM_CTRL_GET_SIZE, &size) > 0) {
            if (size > 0 && demuxer->filepos >= 0)
                ans = MPCLAMP(demuxer->filepos / (double)size, 0, 1);
        }
    }
    if (use_range) {
        if (mpctx->opts->play_frames > 0)
            ans = MPMAX(ans, 1.0 -
                    mpctx->max_frames / (double) mpctx->opts->play_frames);
    }
    return ans;
}

// 0-100, -1 if unknown
int get_percent_pos(struct MPContext *mpctx)
{
    double pos = get_current_pos_ratio(mpctx, false);
    return pos < 0 ? -1 : pos * 100;
}

// -2 is no chapters, -1 is before first chapter
int get_current_chapter(struct MPContext *mpctx)
{
    if (!mpctx->num_chapters)
        return -2;
    double current_pts = get_current_time(mpctx);
    int i;
    for (i = 0; i < mpctx->num_chapters; i++)
        if (current_pts < mpctx->chapters[i].pts)
            break;
    return MPMAX(mpctx->last_chapter_seek, i - 1);
}

char *chapter_display_name(struct MPContext *mpctx, int chapter)
{
    char *name = chapter_name(mpctx, chapter);
    char *dname = NULL;
    if (name) {
        dname = talloc_asprintf(NULL, "(%d) %s", chapter + 1, name);
    } else if (chapter < -1) {
        dname = talloc_strdup(NULL, "(unavailable)");
    } else {
        int chapter_count = get_chapter_count(mpctx);
        if (chapter_count <= 0)
            dname = talloc_asprintf(NULL, "(%d)", chapter + 1);
        else
            dname = talloc_asprintf(NULL, "(%d) of %d", chapter + 1,
                                    chapter_count);
    }
    return dname;
}

// returns NULL if chapter name unavailable
char *chapter_name(struct MPContext *mpctx, int chapter)
{
    if (chapter < 0 || chapter >= mpctx->num_chapters)
        return NULL;
    return mp_tags_get_str(mpctx->chapters[chapter].metadata, "title");
}

// returns the start of the chapter in seconds (NOPTS if unavailable)
double chapter_start_time(struct MPContext *mpctx, int chapter)
{
    if (chapter == -1)
        return 0;
    if (chapter >= 0 && chapter < mpctx->num_chapters)
        return mpctx->chapters[chapter].pts;
    return MP_NOPTS_VALUE;
}

int get_chapter_count(struct MPContext *mpctx)
{
    return mpctx->num_chapters;
}

static void handle_osd_redraw(struct MPContext *mpctx)
{
    if (!mpctx->video_out || !mpctx->video_out->config_ok)
        return;
    // If we're playing normally, let OSD be redrawn naturally as part of
    // video display.
    if (!mpctx->paused) {
        if (mpctx->sleeptime < 0.1 && mpctx->video_status == STATUS_PLAYING)
            return;
    }
    // Don't redraw immediately during a seek (makes it significantly slower).
    bool use_video = mpctx->vo_chain && !mpctx->vo_chain->is_coverart;
    if (use_video && mp_time_sec() - mpctx->start_timestamp < 0.1) {
        mp_set_timeout(mpctx, 0.1);
        return;
    }
    bool want_redraw = osd_query_and_reset_want_redraw(mpctx->osd) ||
                       vo_want_redraw(mpctx->video_out);
    if (!want_redraw)
        return;
    vo_redraw(mpctx->video_out);
}

static void handle_pause_on_low_cache(struct MPContext *mpctx)
{
    bool force_update = false;
    struct MPOpts *opts = mpctx->opts;
    if (!mpctx->demuxer)
        return;

    double now = mp_time_sec();

    struct stream_cache_info c = {.idle = true};
    demux_stream_control(mpctx->demuxer, STREAM_CTRL_GET_CACHE_INFO, &c);

    struct demux_ctrl_reader_state s = {.idle = true, .ts_duration = -1};
    demux_control(mpctx->demuxer, DEMUXER_CTRL_GET_READER_STATE, &s);

    int cache_buffer = 100;
    bool use_pause_on_low_cache = c.size > 0 || mpctx->demuxer->is_network;

    if (mpctx->restart_complete && use_pause_on_low_cache) {
        if (mpctx->paused && mpctx->paused_for_cache) {
            if (!s.underrun && (!opts->cache_pausing || s.idle ||
                                s.ts_duration >= mpctx->cache_wait_time))
            {
                double elapsed_time = now - mpctx->cache_stop_time;
                if (elapsed_time > mpctx->cache_wait_time) {
                    mpctx->cache_wait