/*****************************************************************************

 * lookahead.c: high-level lookahead functions

 *****************************************************************************

 * Copyright (C) 2010-2025 Avail Media and x264 project

 *

 * Authors: Michael Kazmier <mkazmier@availmedia.com>

 *          Alex Giladi <agiladi@availmedia.com>

 *          Steven Walters <kemuri9@gmail.com>

 *

 * This program 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.

 *

 * This program 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 this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA.

 *

 * This program is also available under a commercial proprietary license.

 * For more information, contact us at licensing@x264.com.

 *****************************************************************************/

/* LOOKAHEAD (threaded and non-threaded mode)

 *

 * Lookahead types:

 *     [1] Slice type / scene cut;

 *

 * In non-threaded mode, we run the existing slicetype decision code as it was.

 * In threaded mode, we run in a separate thread, that lives between the calls

 * to x264_encoder_open() and x264_encoder_close(), and performs lookahead for

 * the number of frames specified in rc_lookahead.  Recommended setting is

 * # of bframes + # of threads.

 */

#include "common/common.h"

#include "analyse.h"

static void lookahead_shift( x264_sync_frame_list_t *dst, x264_sync_frame_list_t *src, int count )

{

    int i = count;

    while( i-- )

    {

        assert( dst->i_size < dst->i_max_size );

        assert( src->i_size );

        dst->list[ dst->i_size++ ] = x264_frame_shift( src->list );

        src->i_size--;

    }

    if( count )

    {

        x264_pthread_cond_broadcast( &dst->cv_fill );

        x264_pthread_cond_broadcast( &src->cv_empty );

    }

}

static void lookahead_update_last_nonb( x264_t *h, x264_frame_t *new_nonb )

{

    if( h->lookahead->last_nonb )

        x264_frame_push_unused( h, h->lookahead->last_nonb );

    h->lookahead->last_nonb = new_nonb;

    new_nonb->i_reference_count++;

}

#if HAVE_THREAD

static void lookahead_slicetype_decide( x264_t *h )

{

    x264_slicetype_decide( h );

    lookahead_update_last_nonb( h, h->lookahead->next.list[0] );

    int shift_frames = h->lookahead->next.list[0]->i_bframes + 1;

    x264_pthread_mutex_lock( &h->lookahead->ofbuf.mutex );

    while( h->lookahead->ofbuf.i_size == h->lookahead->ofbuf.i_max_size )

        x264_pthread_cond_wait( &h->lookahead->ofbuf.cv_empty, &h->lookahead->ofbuf.mutex );

    x264_pthread_mutex_lock( &h->lookahead->next.mutex );

    lookahead_shift( &h->lookahead->ofbuf, &h->lookahead->next, shift_frames );

    x264_pthread_mutex_unlock( &h->lookahead->next.mutex );

    /* For MB-tree and VBV lookahead, we have to perform propagation analysis on I-frames too. */

    if( h->lookahead->b_analyse_keyframe && IS_X264_TYPE_I( h->lookahead->last_nonb->i_type ) )

        x264_slicetype_analyse( h, shift_frames );

    x264_pthread_mutex_unlock( &h->lookahead->ofbuf.mutex );

}

REALIGN_STACK static void *lookahead_thread( x264_t *h )

{

    while( 1 )

    {

        x264_pthread_mutex_lock( &h->lookahead->ifbuf.mutex );

        if( h->lookahead->b_exit_thread )

        {

            x264_pthread_mutex_unlock( &h->lookahead->ifbuf.mutex );

            break;

        }

        x264_pthread_mutex_lock( &h->lookahead->next.mutex );

        int shift = X264_MIN( h->lookahead->next.i_max_size - h->lookahead->next.i_size, h->lookahead->ifbuf.i_size );

        lookahead_shift( &h->lookahead->next, &h->lookahead->ifbuf, shift );

        x264_pthread_mutex_unlock( &h->lookahead->next.mutex );

        if( h->lookahead->next.i_size <= h->lookahead->i_slicetype_length + h->param.b_vfr_input )

        {

            while( !h->lookahead->ifbuf.i_size && !h->lookahead->b_exit_thread )

                x264_pthread_cond_wait( &h->lookahead->ifbuf.cv_fill, &h->lookahead->ifbuf.mutex );

            x264_pthread_mutex_unlock( &h->lookahead->ifbuf.mutex );

        }

        else

        {

            x264_pthread_mutex_unlock( &h->lookahead->ifbuf.mutex );

            lookahead_slicetype_decide( h );

        }

    }   /* end of input frames */

    x264_pthread_mutex_lock( &h->lookahead->ifbuf.mutex );

    x264_pthread_mutex_lock( &h->lookahead->next.mutex );

    lookahead_shift( &h->lookahead->next, &h->lookahead->ifbuf, h->lookahead->ifbuf.i_size );

    x264_pthread_mutex_unlock( &h->lookahead->next.mutex );

    x264_pthread_mutex_unlock( &h->lookahead->ifbuf.mutex );

    while( h->lookahead->next.i_size )

        lookahead_slicetype_decide( h );

    x264_pthread_mutex_lock( &h->lookahead->ofbuf.mutex );

    h->lookahead->b_thread_active = 0;

    x264_pthread_cond_broadcast( &h->lookahead->ofbuf.cv_fill );

    x264_pthread_mutex_unlock( &h->lookahead->ofbuf.mutex );

    return NULL;

}

#endif

int x264_lookahead_init( x264_t *h, int i_slicetype_length )

{

    x264_lookahead_t *look;

    CHECKED_MALLOCZERO( look, sizeof(x264_lookahead_t) );

    for( int i = 0; i < h->param.i_threads; i++ )

        h->thread[i]->lookahead = look;

    look->i_last_keyframe = - h->param.i_keyint_max;

    look->b_analyse_keyframe = (h->param.rc.b_mb_tree || (h->param.rc.i_vbv_buffer_size && h->param.rc.i_lookahead))

                               && !h->param.rc.b_stat_read;

    look->i_slicetype_length = i_slicetype_length;

    /* init frame lists */

    if( x264_sync_frame_list_init( &look->ifbuf, h->param.i_sync_lookahead+3 ) ||

        x264_sync_frame_list_init( &look->next, h->frames.i_delay+3 ) ||

        x264_sync_frame_list_init( &look->ofbuf, h->frames.i_delay+3 ) )

        goto fail;

    if( !h->param.i_sync_lookahead )

        return 0;

    x264_t *look_h = h->thread[h->param.i_threads];

    *look_h = *h;

    if( x264_macroblock_cache_allocate( look_h ) )

        goto fail;

    if( x264_macroblock_thread_allocate( look_h, 1 ) < 0 )

        goto fail;

    if( x264_pthread_create( &look->thread_handle, NULL, (void*)lookahead_thread, look_h ) )

        goto fail;

    look->b_thread_active = 1;

    return 0;

fail:

    x264_free( look );

    return -1;

}

Unexecuted instantiation: x264_8_lookahead_init

Unexecuted instantiation: x264_10_lookahead_init

void x264_lookahead_delete( x264_t *h )

{

    if( h->param.i_sync_lookahead )

    {

        x264_pthread_mutex_lock( &h->lookahead->ifbuf.mutex );

        h->lookahead->b_exit_thread = 1;

        x264_pthread_cond_broadcast( &h->lookahead->ifbuf.cv_fill );

        x264_pthread_mutex_unlock( &h->lookahead->ifbuf.mutex );

        x264_pthread_join( h->lookahead->thread_handle, NULL );

        x264_macroblock_cache_free( h->thread[h->param.i_threads] );

        x264_macroblock_thread_free( h->thread[h->param.i_threads], 1 );

        x264_free( h->thread[h->param.i_threads] );

    }

    x264_sync_frame_list_delete( &h->lookahead->ifbuf );

    x264_sync_frame_list_delete( &h->lookahead->next );

    if( h->lookahead->last_nonb )

        x264_frame_push_unused( h, h->lookahead->last_nonb );

    x264_sync_frame_list_delete( &h->lookahead->ofbuf );

    x264_free( h->lookahead );

}

Unexecuted instantiation: x264_8_lookahead_delete

Unexecuted instantiation: x264_10_lookahead_delete

void x264_lookahead_put_frame( x264_t *h, x264_frame_t *frame )

{

    if( h->param.i_sync_lookahead )

        x264_sync_frame_list_push( &h->lookahead->ifbuf, frame );

    else

        x264_sync_frame_list_push( &h->lookahead->next, frame );

}

Unexecuted instantiation: x264_8_lookahead_put_frame

Unexecuted instantiation: x264_10_lookahead_put_frame

int x264_lookahead_is_empty( x264_t *h )

{

    x264_pthread_mutex_lock( &h->lookahead->ofbuf.mutex );

    x264_pthread_mutex_lock( &h->lookahead->next.mutex );

    int b_empty = !h->lookahead->next.i_size && !h->lookahead->ofbuf.i_size;

    x264_pthread_mutex_unlock( &h->lookahead->next.mutex );

    x264_pthread_mutex_unlock( &h->lookahead->ofbuf.mutex );

    return b_empty;

}

Unexecuted instantiation: x264_8_lookahead_is_empty

Unexecuted instantiation: x264_10_lookahead_is_empty

static void lookahead_encoder_shift( x264_t *h )

{

    if( !h->lookahead->ofbuf.i_size )

        return;

    int i_frames = h->lookahead->ofbuf.list[0]->i_bframes + 1;

    while( i_frames-- )

    {

        x264_frame_push( h->frames.current, x264_frame_shift( h->lookahead->ofbuf.list ) );

        h->lookahead->ofbuf.i_size--;

    }

    x264_pthread_cond_broadcast( &h->lookahead->ofbuf.cv_empty );

}

void x264_lookahead_get_frames( x264_t *h )

{

    if( h->param.i_sync_lookahead )

    {   /* We have a lookahead thread, so get frames from there */

        x264_pthread_mutex_lock( &h->lookahead->ofbuf.mutex );

        while( !h->lookahead->ofbuf.i_size && h->lookahead->b_thread_active )

            x264_pthread_cond_wait( &h->lookahead->ofbuf.cv_fill, &h->lookahead->ofbuf.mutex );

        lookahead_encoder_shift( h );

        x264_pthread_mutex_unlock( &h->lookahead->ofbuf.mutex );

    }

    else

    {   /* We are not running a lookahead thread, so perform all the slicetype decide on the fly */

        if( h->frames.current[0] || !h->lookahead->next.i_size )

            return;

        x264_slicetype_decide( h );

        lookahead_update_last_nonb( h, h->lookahead->next.list[0] );

        int shift_frames = h->lookahead->next.list[0]->i_bframes + 1;

        lookahead_shift( &h->lookahead->ofbuf, &h->lookahead->next, shift_frames );

        /* For MB-tree and VBV lookahead, we have to perform propagation analysis on I-frames too. */

        if( h->lookahead->b_analyse_keyframe && IS_X264_TYPE_I( h->lookahead->last_nonb->i_type ) )

            x264_slicetype_analyse( h, shift_frames );

        lookahead_encoder_shift( h );

    }

}

Unexecuted instantiation: x264_8_lookahead_get_frames

Unexecuted instantiation: x264_10_lookahead_get_frames