libmpeg2.c

video linux conference

/*****************************************************************************
 * libmpeg2.c: mpeg2 video decoder module making use of libmpeg2.
 *****************************************************************************
 * Copyright (C) 1999-2001 VideoLAN
 * $Id: libmpeg2.c 11086 2005-05-20 18:00:02Z massiot $
 *
 * Authors: Gildas Bazin <[e-mail]>
 *          Christophe Massiot <[e-mail]>
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include <vlc/vlc.h>
#include <vlc/vout.h>
#include <vlc/decoder.h>

#include <mpeg2dec/mpeg2.h>

#include "vout_synchro.h"

/* Aspect ratio (ISO/IEC 13818-2 section 6.3.3, table 6-3) */
#define AR_SQUARE_PICTURE       1                           /* square pixels */
#define AR_3_4_PICTURE          2                        /* 3:4 picture (TV) */
#define AR_16_9_PICTURE         3              /* 16:9 picture (wide screen) */
#define AR_221_1_PICTURE        4                  /* 2.21:1 picture (movie) */

/*****************************************************************************
 * decoder_sys_t : libmpeg2 decoder descriptor
 *****************************************************************************/
struct decoder_sys_t
{
    /*
     * libmpeg2 properties
     */
    mpeg2dec_t          *p_mpeg2dec;
    const mpeg2_info_t  *p_info;
    vlc_bool_t          b_skip;

    /*
     * Input properties
     */
    mtime_t          i_previous_pts;
    mtime_t          i_current_pts;
    mtime_t          i_previous_dts;
    mtime_t          i_current_dts;
    int              i_current_rate;
    picture_t *      p_picture_to_destroy;
    vlc_bool_t       b_garbage_pic;
    vlc_bool_t       b_after_sequence_header; /* is it the next frame after
                                               * the sequence header ?    */
    vlc_bool_t       b_slice_i;             /* intra-slice refresh stream */

    vlc_bool_t      b_preroll;

    /*
     * Output properties
     */
    vout_synchro_t *p_synchro;
    int            i_aspect;
    mtime_t        i_last_frame_pts;

};

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  OpenDecoder( vlc_object_t * );
static void CloseDecoder( vlc_object_t * );

static picture_t *DecodeBlock( decoder_t *, block_t ** );

static picture_t *GetNewPicture( decoder_t *, uint8_t ** );

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
vlc_module_begin();
    set_description( _("MPEG I/II video decoder (using libmpeg2)") );
    set_capability( "decoder", 150 );
    set_category( CAT_INPUT );
    set_subcategory( SUBCAT_INPUT_VCODEC );
    set_callbacks( OpenDecoder, CloseDecoder );
    add_shortcut( "libmpeg2" );
vlc_module_end();

/*****************************************************************************
 * OpenDecoder: probe the decoder and return score
 *****************************************************************************/
static int OpenDecoder( vlc_object_t *p_this )
{
    decoder_t *p_dec = (decoder_t*)p_this;
    decoder_sys_t *p_sys;
    uint32_t i_accel = 0;

    if( p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','v') &&
        p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','1') &&
        /* Pinnacle hardware-mpeg1 */
        p_dec->fmt_in.i_codec != VLC_FOURCC('P','I','M','1') &&
        /* ATI Video */
        p_dec->fmt_in.i_codec != VLC_FOURCC('V','C','R','2') &&
        p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','2') )
    {
        return VLC_EGENERIC;
    }

    /* Allocate the memory needed to store the decoder's structure */
    if( ( p_dec->p_sys = p_sys =
          (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
    {
        msg_Err( p_dec, "out of memory" );
        return VLC_EGENERIC;
    }

    /* Initialize the thread properties */
    memset( p_sys, 0, sizeof(decoder_sys_t) );
    p_sys->p_mpeg2dec = NULL;
    p_sys->p_synchro  = NULL;
    p_sys->p_info     = NULL;
    p_sys->i_current_pts  = 0;
    p_sys->i_previous_pts = 0;
    p_sys->i_current_dts  = 0;
    p_sys->i_previous_dts = 0;
    p_sys->p_picture_to_destroy = NULL;
    p_sys->b_garbage_pic = 0;
    p_sys->b_slice_i  = 0;
    p_sys->b_skip     = 0;
    p_sys->b_preroll = VLC_FALSE;

#if defined( __i386__ ) || defined( __x86_64__ )
    if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_MMX )
    {
        i_accel |= MPEG2_ACCEL_X86_MMX;
    }

    if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_3DNOW )
    {
        i_accel |= MPEG2_ACCEL_X86_3DNOW;
    }

    if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_MMXEXT )
    {
        i_accel |= MPEG2_ACCEL_X86_MMXEXT;
    }

#elif defined( __powerpc__ ) || defined( SYS_DARWIN )
    if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_ALTIVEC )
    {
        i_accel |= MPEG2_ACCEL_PPC_ALTIVEC;
    }

#else
    /* If we do not know this CPU, trust libmpeg2's feature detection */
    i_accel = MPEG2_ACCEL_DETECT;

#endif

    /* Set CPU acceleration features */
    mpeg2_accel( i_accel );

    /* Initialize decoder */
    p_sys->p_mpeg2dec = mpeg2_init();
    if( p_sys->p_mpeg2dec == NULL)
    {
        msg_Err( p_dec, "mpeg2_init() failed" );
        free( p_sys );
        return VLC_EGENERIC;
    }

    p_sys->p_info = mpeg2_info( p_sys->p_mpeg2dec );

    p_dec->pf_decode_video = DecodeBlock;

    return VLC_SUCCESS;
}

/*****************************************************************************
 * RunDecoder: the libmpeg2 decoder
 *****************************************************************************/
static picture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
{
    decoder_sys_t   *p_sys = p_dec->p_sys;
    mpeg2_state_t   state;
    picture_t       *p_pic;

    block_t *p_block;

    if( !pp_block || !*pp_block ) return NULL;

    p_block = *pp_block;

    while( 1 )
    {
        state = mpeg2_parse( p_sys->p_mpeg2dec );

        switch( state )
        {
        case STATE_BUFFER:
            if( !p_block->i_buffer )
            {
                block_Release( p_block );
                return NULL;
            }

            if( (p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY
                                      | BLOCK_FLAG_CORRUPTED)) &&
                p_sys->p_synchro &&
                p_sys->p_info->sequence &&
                p_sys->p_info->sequence->width != (unsigned)-1 )
            {
                vout_SynchroReset( p_sys->p_synchro );
                if( p_sys->p_info->current_fbuf != NULL
                    && p_sys->p_info->current_fbuf->id != NULL )
                {
                    p_sys->b_garbage_pic = 1;
                    p_pic = p_sys->p_info->current_fbuf->id;
                }
                else
                {
                    uint8_t *buf[3];
                    buf[0] = buf[1] = buf[2] = NULL;
                    if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
                        break;
                    mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
                }
                p_sys->p_picture_to_destroy = p_pic;

                if ( p_sys->b_slice_i )
                {
                    vout_SynchroNewPicture( p_sys->p_synchro,
                        I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate,
                        p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY );
                    vout_SynchroDecode( p_sys->p_synchro );
                    vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
                }
            }

            if( p_block->i_flags & BLOCK_FLAG_PREROLL )
            {
                p_sys->b_preroll = VLC_TRUE;
            }
            else if( p_sys->b_preroll )
            {
                p_sys->b_preroll = VLC_FALSE;
                /* Reset synchro */
                vout_SynchroReset( p_sys->p_synchro );
            }

#ifdef PIC_FLAG_PTS
            if( p_block->i_pts )
            {
                mpeg2_pts( p_sys->p_mpeg2dec, (uint32_t)p_block->i_pts );

#else /* New interface */
            if( p_block->i_pts || p_block->i_dts )
            {
                mpeg2_tag_picture( p_sys->p_mpeg2dec,
                                   (uint32_t)p_block->i_pts,
                                   (uint32_t)p_block->i_dts );
#endif
                p_sys->i_previous_pts = p_sys->i_current_pts;
                p_sys->i_current_pts = p_block->i_pts;
                p_sys->i_previous_dts = p_sys->i_current_dts;
                p_sys->i_current_dts = p_block->i_dts;
            }

            p_sys->i_current_rate = p_block->i_rate;

            mpeg2_buffer( p_sys->p_mpeg2dec, p_block->p_buffer,
                          p_block->p_buffer + p_block->i_buffer );

            p_block->i_buffer = 0;
            break;

        case STATE_SEQUENCE:
        {
            /* Initialize video output */
            uint8_t *buf[3];
            buf[0] = buf[1] = buf[2] = NULL;

            /* Check whether the input gave a particular aspect ratio */
            if( p_dec->fmt_in.video.i_aspect )
            {
                p_sys->i_aspect = p_dec->fmt_in.video.i_aspect;
                if( p_sys->i_aspect <= AR_221_1_PICTURE )
                switch( p_sys->i_aspect )
                {
                case AR_3_4_PICTURE:
                    p_sys->i_aspect = VOUT_ASPECT_FACTOR * 4 / 3;
                    break;
                case AR_16_9_PICTURE:
                    p_sys->i_aspect = VOUT_ASPECT_FACTOR * 16 / 9;
                    break;
                case AR_221_1_PICTURE:
                    p_sys->i_aspect = VOUT_ASPECT_FACTOR * 221 / 100;
                    break;
                case AR_SQUARE_PICTURE:
                    p_sys->i_aspect = VOUT_ASPECT_FACTOR *
                                   p_sys->p_info->sequence->width /
                                   p_sys->p_info->sequence->height;
                    break;
                }
            }
            else
            {
                /* Use the value provided in the MPEG sequence header */
                if( p_sys->p_info->sequence->pixel_height > 0 )
                {
                    p_sys->i_aspect =
                        ((uint64_t)p_sys->p_info->sequence->display_width) *
                        p_sys->p_info->sequence->pixel_width *
                        VOUT_ASPECT_FACTOR /
                        p_sys->p_info->sequence->display_height /
                        p_sys->p_info->sequence->pixel_height;
                }
                else