path: root/demux/demux.c

/*
 * This file is part of MPlayer.
 *
 * MPlayer 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.
 *
 * MPlayer 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 MPlayer; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <unistd.h>
#include <pthread.h>

#include <math.h>

#include <sys/types.h>
#include <sys/stat.h>

#include "config.h"
#include "options/options.h"
#include "talloc.h"
#include "common/msg.h"
#include "common/global.h"

#include "stream/stream.h"
#include "demux.h"
#include "stheader.h"
#include "mf.h"

#include "audio/format.h"

// Demuxer list
extern const struct demuxer_desc demuxer_desc_edl;
extern const struct demuxer_desc demuxer_desc_cue;
extern const demuxer_desc_t demuxer_desc_rawaudio;
extern const demuxer_desc_t demuxer_desc_rawvideo;
extern const demuxer_desc_t demuxer_desc_tv;
extern const demuxer_desc_t demuxer_desc_mf;
extern const demuxer_desc_t demuxer_desc_matroska;
extern const demuxer_desc_t demuxer_desc_lavf;
extern const demuxer_desc_t demuxer_desc_libass;
extern const demuxer_desc_t demuxer_desc_subreader;
extern const demuxer_desc_t demuxer_desc_playlist;
extern const demuxer_desc_t demuxer_desc_disc;

/* Please do not add any new demuxers here. If you want to implement a new
 * demuxer, add it to libavformat, except for wrappers around external
 * libraries and demuxers requiring binary support. */

const demuxer_desc_t *const demuxer_list[] = {
    &demuxer_desc_disc,
    &demuxer_desc_edl,
    &demuxer_desc_cue,
    &demuxer_desc_rawaudio,
    &demuxer_desc_rawvideo,
#if HAVE_TV
    &demuxer_desc_tv,
#endif
#if HAVE_LIBASS
    &demuxer_desc_libass,
#endif
    &demuxer_desc_matroska,
    &demuxer_desc_lavf,
    &demuxer_desc_mf,
    &demuxer_desc_playlist,
    // Pretty aggressive, so should be last.
    &demuxer_desc_subreader,
    NULL
};

struct demux_internal {
    struct mp_log *log;

    // The demuxer runs potentially in another thread, so we keep two demuxer
    // structs; the real demuxer can access the shadow struct only.
    // Since demuxer and user threads both don't use locks, a third demuxer
    // struct d_buffer is used to copy data between them in a synchronized way.
    struct demuxer *d_thread;   // accessed by demuxer impl. (producer)
    struct demuxer *d_user;     // accessed by player (consumer)
    struct demuxer *d_buffer;   // protected by lock; used to sync d_user/thread

    // The lock protects the packet queues (struct demux_stream), d_buffer,
    // and some minor fields like thread_paused.
    pthread_mutex_t lock;
    pthread_cond_t wakeup;
    pthread_t thread;

    // -- All the following fields are protected by lock.

    bool thread_paused;
    int thread_request_pause;   // counter, if >0, make demuxer thread pause
    bool thread_terminate;
    bool threading;
    void (*wakeup_cb)(void *ctx);
    void *wakeup_cb_ctx;

    bool warned_queue_overflow;
    bool last_eof;              // last actual global EOF status
    bool eof;                   // whether we're in EOF state (reset for retry)
    bool idle;
    bool autoselect;
    double min_secs;
    int min_packs;
    int min_bytes;

    bool tracks_switched;       // thread needs to inform demuxer of this

    bool seeking;               // there's a seek queued
    int seek_flags;             // flags for next seek (if seeking==true)
    double seek_pts;

    // Cached state.
    double time_length;
    struct mp_tags *stream_metadata;
    int64_t stream_size;
    int64_t stream_cache_size;
    int64_t stream_cache_fill;
    int stream_cache_idle;
};

struct demux_stream {
    struct demux_internal *in;
    enum stream_type type;
    // all fields are protected by in->lock
    bool selected;          // user wants packets from this stream
    bool active;            // try to keep at least 1 packet queued
    bool eof;               // end of demuxed stream? (true if all buffer empty)
    size_t packs;           // number of packets in buffer
    size_t bytes;           // total bytes of packets in buffer
    double base_ts;         // timestamp of the last packet returned to decoder
    double last_ts;         // timestamp of the last packet added to queue
    struct demux_packet *head;
    struct demux_packet *tail;
};

// If one of the values is NOPTS, always pick the other one.
#define MP_PTS_MIN(a, b) ((a) == MP_NOPTS_VALUE || ((a) > (b)) ? (b) : (a))
#define MP_PTS_MAX(a, b) ((a) == MP_NOPTS_VALUE || ((a) < (b)) ? (b) : (a))

static void demuxer_sort_chapters(demuxer_t *demuxer);
static void *demux_thread(void *pctx);
static void update_cache(struct demux_internal *in);

// called locked
static void ds_flush(struct demux_stream *ds)
{
    demux_packet_t *dp = ds->head;
    while (dp) {
        demux_packet_t *dn = dp->next;
        free_demux_packet(dp);
        dp = dn;
    }
    ds->head = ds->tail = NULL;
    ds->packs = 0;
    ds->bytes = 0;
    ds->last_ts = ds->base_ts = MP_NOPTS_VALUE;
    ds->eof = false;
    ds->active = false;
}

struct sh_stream *new_sh_stream(demuxer_t *demuxer, enum stream_type type)
{
    assert(demuxer == demuxer->in->d_thread);

    if (demuxer->num_streams > MAX_SH_STREAMS) {
        MP_WARN(demuxer, "Too many streams.\n");
        return NULL;
    }

    int demuxer_id = 0;
    for (int n = 0; n < demuxer->num_streams; n++) {
        if (demuxer->streams[n]->type == type)
            demuxer_id++;
    }

    struct sh_stream *sh = talloc_ptrtype(demuxer, sh);
    *sh = (struct sh_stream) {
        .type = type,
        .index = demuxer->num_streams,
        .demuxer_id = demuxer_id, // may be overwritten by demuxer
        .ds = talloc(sh, struct demux_stream),
    };
    *sh->ds = (struct demux_stream) {
        .in = demuxer->in,
        .type = sh->type,
        .selected = demuxer->in->autoselect,
    };
    MP_TARRAY_APPEND(demuxer, demuxer->streams, demuxer->num_streams, sh);
    switch (sh->type) {
    case STREAM_VIDEO: sh->video = talloc_zero(demuxer, struct sh_video); break;
    case STREAM_AUDIO: sh->audio = talloc_zero(demuxer, struct sh_audio); break;
    case STREAM_SUB:   sh->sub = talloc_zero(demuxer, struct sh_sub); break;
    }

    return sh;
}

void free_demuxer(demuxer_t *demuxer)
{
    if (!demuxer)
        return;
    struct demux_internal *in = demuxer->in;
    assert(demuxer == in->d_user);

    demux_stop_thread(demuxer);

    if (demuxer->desc->close)
        demuxer->desc->close(in->d_thread);
    for (int n = 0; n < demuxer->num_streams; n++)
        ds_flush(demuxer->streams[n]->ds);
    pthread_mutex_destroy(&in->lock);
    pthread_cond_destroy(&in->wakeup);
    talloc_free(demuxer);
}

// Start the demuxer thread, which reads ahead packets on its own.
void demux_start_thread(struct demuxer *demuxer)
{
    struct demux_internal *in = demuxer->in;
    assert(demuxer == in->d_user);

    if (!in->threading) {
        in->threading = true;
        if (pthread_create(&in->thread, NULL, demux_thread, in))
            in->threading = false;
    }
}

void demux_stop_thread(struct demuxer *demuxer)
{
    struct demux_internal *in = demuxer->in;
    assert(demuxer == in->d_user);

    if (in->threading) {
        pthread_mutex_lock(&in->lock);
        in->thread_terminate = true;
        pthread_cond_signal(&in->wakeup);
        pthread_mutex_unlock(&in->lock);
        pthread_join(in->thread, NULL);
        in->threading = false;
        in->thread_terminate = false;
    }
}

// The demuxer thread will call cb(ctx) if there's a new packet, or EOF is reached.
void demux_set_wakeup_cb(struct demuxer *demuxer, void (*cb)(void *ctx), void *ctx)
{
    struct demux_internal *in = demuxer->in;
    pthread_mutex_lock(&in->lock);
    in->wakeup_cb = cb;
    in->wakeup_cb_ctx = ctx;
    pthread_mutex_unlock(&in->lock);
}

const char *stream_type_name(enum stream_type type)
{
    switch (type) {
    case STREAM_VIDEO:  return "video";
    case STREAM_AUDIO:  return "audio";
    case STREAM_SUB:    return "sub";
    default:            return "unknown";
    }
}

// Returns the same value as demuxer->fill_buffer: 1 ok, 0 EOF/not selected.
int demux_add_packet(struct sh_stream *stream, demux_packet_t *dp)
{
    struct demux_stream *ds = stream ? stream->ds : NULL;
    if (!dp || !ds) {
        talloc_free(dp);
        return 0;
    }
    struct demux_internal *in = ds->in;
    pthread_mutex_lock(&in->lock);
    if (!ds->selected || in->seeking) {
        pthread_mutex_unlock(&in->lock);
        talloc_free(dp);
        return 0;
    }

    dp->stream = stream->index;
    dp->next = NULL;

    ds->packs++;
    ds->bytes += dp->len;
    if (ds->tail) {
        // next packet in stream
        ds->tail->next = dp;
        ds->tail = dp;
    } else {
        // first packet in stream
        ds->head = ds->tail = dp;
    }

    // obviously not true anymore
    ds->eof = false;
    in->last_eof = in->eof = false;

    // For video, PTS determination is not trivial, but for other media types
    // distinguishing PTS and DTS is not useful.
    if (stream->type != STREAM_VIDEO && dp->pts == MP_NOPTS_VALUE)
        dp->pts = dp->dts;

    double ts = dp->dts == MP_NOPTS_VALUE ? dp->pts : dp->dts;
    if (ts != MP_NOPTS_VALUE && (ts > ds->last_ts || ts + 10 < ds->last_ts))
        ds->last_ts = ts;
    if (ds->base_ts == MP_NOPTS_VALUE)
        ds->base_ts = ds->last_ts;

    MP_DBG(in, "append packet to %s: size=%d pts=%f dts=%f pos=%"PRIi64" "
           "[num=%zd size=%zd]\n", stream_type_name(stream->type),
           dp->len, dp->pts, dp->dts, dp->pos, ds->packs, ds->bytes);

    if (ds->in->wakeup_cb && !ds->head->next)
        ds->in->wakeup_cb(ds->in->wakeup_cb_ctx);
    pthread_cond_signal(&in->wakeup);
    pthread_mutex_unlock(&in->lock);
    return 1;
}

// Returns true if there was "progress" (lock was released temporarily).
static bool read_packet(struct demux_internal *in)
{
    in->eof = false;
    in->idle = true;

    // Check if we need to read a new packet. We do this if all queues are below
    // the minimum, or if a stream explicitly needs new packets. Also includes
    // safe-guards against packet queue overflow.
    bool active = false, read_more = false;
    size_t packs = 0, bytes = 0;
    for (int n = 0; n < in->d_buffer->num_streams; n++) {
        struct demux_stream *ds = in->d_buffer->streams[n]->ds;
        active |= ds->active;
        read_more |= ds->active && !ds->head;
        packs += ds->packs;
        bytes += ds->bytes;
        if (ds->active && ds->last_ts != MP_NOPTS_VALUE && in->min_secs > 0)
            read_more |= ds->last_ts - ds->base_ts < in->min_secs;
    }
    MP_DBG(in, "packets=%zd, bytes=%zd, active=%d, more=%d\n",
           packs, bytes, active, read_more);
    if (packs >= MAX_PACKS || bytes >= MAX_PACK_BYTES) {
        if (!in->warned_queue_overflow) {
            in->warned_queue_overflow = true;
            MP_ERR(in, "Too many packets in the demuxer packet queues:\n");
            for (int n = 0; n < in->d_buffer->num_streams; n++) {
                struct demux_stream *ds = in->d_buffer->streams[n]->ds;
                if (ds->selected) {
                    MP_ERR(in, "  %s/%d: %zd packets, %zd bytes\n",
                           stream_type_name(ds->type), n, ds->packs, ds->bytes);
                }
            }
        }
        for (int n = 0; n < in->d_buffer->num_streams; n++) {
            struct demux_stream *ds = in->d_buffer->streams[n]->ds;
            ds->eof |= !ds->head;
        }
        pthread_cond_signal(&in->wakeup);
        return false;
    }
    if (packs < in->min_packs && bytes < in->min_bytes)
        read_more |= active;

    if (!read_more)
        return false;

    // Actually read a packet. Drop the lock while doing so, because waiting
    // for disk or network I/O can take time.
    in->idle = false;
    pthread_mutex_unlock(&in->lock);
    struct demuxer *demux = in->d_thread;
    bool eof = !demux->desc->fill_buffer || demux->desc->fill_buffer(demux) <= 0;
    pthread_mutex_lock(&in->lock);

    update_cache(in);

    if (eof) {
        for (int n = 0; n < in->d_buffer->num_streams; n++) {
            struct demux_stream *ds = in->d_buffer->streams[n]->ds;
            ds->eof = true;
            ds->active = false;
        }
        // If we had EOF previously, then don't wakeup (avoids wakeup loop)
        if (!in->last_eof) {
            if (in->wakeup_cb)
                in->wakeup_cb(in->wakeup_cb_ctx);
            pthread_cond_signal(&in->wakeup);
            MP_VERBOSE(in, "EOF reached.\n");
        }
    }
    in->eof = in->last_eof = eof;
    return true;
}

// must be called locked; may temporarily unlock
static void ds_get_packets(struct demux_stream *ds)
{
    const char *t = stream_type_name(ds->type);
    struct demux_internal *in = ds->in;
    MP_DBG(in, "reading packet for %s\n", t);
    in->eof = false; // force retry
    ds->eof = false;
    while (ds->selected && !ds->head && !ds->eof) {
        ds->active = true;
        // Note: the following code marks EOF if it can't continue
        if (in->threading) {
            MP_VERBOSE(in, "waiting for demux thread (%s)\n", t);
            pthread_cond_signal(&in->wakeup);
            pthread_cond_wait(&in->wakeup, &in->lock);
        } else {
            read_packet(in);
        }
    }
}

static void execute_trackswitch(struct demux_internal *in)
{
    in->tracks_switched = false;

    pthread_mutex_unlock(&in->lock);

    if (in->d_thread->desc->control)
        in->d_thread->desc->control(in->d_thread, DEMUXER_CTRL_SWITCHED_TRACKS, 0);

    pthread_mutex_lock(&in->lock);
}

static void execute_seek(struct demux_internal *in)
{
    int flags = in->seek_flags;
    double pts = in->seek_pts;
    in->seeking = false;

    pthread_mutex_unlock(&in->lock);

    if (in->d_thread->desc->seek)
        in->d_thread->desc->seek(in->d_thread, pts, flags);

    pthread_mutex_lock(&in->lock);
}

static void *demux_thread(void *pctx)
{
    struct demux_internal *in = pctx;
    pthread_mutex_lock(&in->lock);
    while (!in->thread_terminate) {
        in->thread_paused = in->thread_request_pause > 0;
        if (in->thread_paused) {
            pthread_cond_signal(&in->wakeup);
            pthread_cond_wait(&in->wakeup, &in->lock);
            continue;
        }
        if (in->tracks_switched) {
            execute_trackswitch(in);
            continue;
        }
        if (in->seeking) {
            execute_seek(in);
            continue;
        }
        if (!in->eof) {
            if (read_packet(in))
                continue; // read_packet unlocked, so recheck conditions
        }
        update_cache(in);
        pthread_cond_signal(&in->wakeup);
        pthread_cond_wait(&in->wakeup, &in->lock);
    }
    pthread_mutex_unlock(&in->lock);
    return NULL;
}

static struct demux_packet *dequeue_packet(struct demux_stream *ds)
{
    if (!ds->head)
        return NULL;
    struct demux_packet *pkt = ds->head;
    ds->head = pkt->next;
    pkt->next = NULL;
    if (!ds->head)
        ds->tail = NULL;
    ds->bytes -= pkt->l