h264.c

VLC Player Source Code

    }

    return VLC_SUCCESS;
}

/*****************************************************************************
 * Close: clean up the packetizer
 *****************************************************************************/
static void Close( vlc_object_t *p_this )
{
    decoder_t *p_dec = (decoder_t*)p_this;
    decoder_sys_t *p_sys = p_dec->p_sys;
    int i;

    if( p_sys->p_frame ) block_ChainRelease( p_sys->p_frame );
    for( i = 0; i < SPS_MAX; i++ )
    {
        if( p_sys->pp_sps[i] )
            block_Release( p_sys->pp_sps[i] );
    }
    for( i = 0; i < PPS_MAX; i++ )
    {
        if( p_sys->pp_pps[i] )
            block_Release( p_sys->pp_pps[i] );
    }
    block_BytestreamRelease( &p_sys->bytestream );
    free( p_sys );
}

/****************************************************************************
 * Packetize: the whole thing
 * Search for the startcodes 3 or more bytes
 * Feed ParseNALBlock ALWAYS with 4 byte startcode prepended NALs
 ****************************************************************************/
static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    block_t       *p_pic;

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

    if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
    {
        if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
        {
            p_sys->i_state = STATE_NOSYNC;
            block_BytestreamFlush( &p_sys->bytestream );

            if( p_sys->p_frame )
                block_ChainRelease( p_sys->p_frame );
            p_sys->p_frame = NULL;
            p_sys->slice.i_frame_type = 0;
            p_sys->b_slice = false;
        }
        block_Release( *pp_block );
        return NULL;
    }

    block_BytestreamPush( &p_sys->bytestream, *pp_block );

    for( ;; )
    {
        bool b_used_ts;

        switch( p_sys->i_state )
        {
            case STATE_NOSYNC:
                /* Skip until 3 byte startcode 0 0 1 */
                if( block_FindStartcodeFromOffset( &p_sys->bytestream,
                      &p_sys->i_offset, p_sys->startcode+1, 3 ) == VLC_SUCCESS)
                {
                    p_sys->i_state = STATE_NEXT_SYNC;
                }

                if( p_sys->i_offset )
                {
                    /* skip the data */
                    block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
                    p_sys->i_offset = 0;
                    block_BytestreamFlush( &p_sys->bytestream );
                }

                if( p_sys->i_state != STATE_NEXT_SYNC )
                {
                    /* Need more data */
                    return NULL;
                }

                p_sys->i_offset = 1; /* To find next startcode */

            case STATE_NEXT_SYNC:
                /* Find the next 3 byte startcode 0 0 1*/
                if( block_FindStartcodeFromOffset( &p_sys->bytestream,
                      &p_sys->i_offset, p_sys->startcode+1, 3 ) != VLC_SUCCESS)
                {
                    /* Need more data */
                    return NULL;
                }
                block_BytestreamFlush( &p_sys->bytestream );

                /* Get the new fragment and set the pts/dts */
                block_t *p_block_bytestream = p_sys->bytestream.p_block;

                p_pic = block_New( p_dec, p_sys->i_offset +1 );
                p_pic->i_pts = p_block_bytestream->i_pts;
                p_pic->i_dts = p_block_bytestream->i_dts;

                /* Force 4 byte startcode 0 0 0 1 */
                p_pic->p_buffer[0] = 0;

                block_GetBytes( &p_sys->bytestream, &p_pic->p_buffer[1],
                                p_pic->i_buffer-1 );

                /* Remove trailing 0 bytes */
                while( p_pic->i_buffer && (!p_pic->p_buffer[p_pic->i_buffer-1] ) )
                    p_pic->i_buffer--;
                p_sys->i_offset = 0;

                /* Parse the NAL */
                p_pic = ParseNALBlock( p_dec, &b_used_ts, p_pic );
                if( b_used_ts )
                {
                    p_block_bytestream->i_dts = -1;
                    p_block_bytestream->i_pts = -1;
                }

                if( !p_pic )
                {
                    p_sys->i_state = STATE_NOSYNC;
                    break;
                }
#if 0
                msg_Dbg( p_dec, "pts=%"PRId64" dts=%"PRId64,
                         p_pic->i_pts, p_pic->i_dts );
#endif

                /* So p_block doesn't get re-added several times */
                *pp_block = block_BytestreamPop( &p_sys->bytestream );

                p_sys->i_state = STATE_NOSYNC;

                return p_pic;
        }
    }
}

/****************************************************************************
 * PacketizeAVC1: Takes VCL blocks of data and creates annexe B type NAL stream
 * Will always use 4 byte 0 0 0 1 startcodes
 * Will prepend a SPS and PPS before each keyframe
 ****************************************************************************/
static block_t *PacketizeAVC1( decoder_t *p_dec, block_t **pp_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    block_t       *p_block;
    block_t       *p_ret = NULL;
    uint8_t       *p;

    if( !pp_block || !*pp_block )
        return NULL;
    if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
    {
        block_Release( *pp_block );
        return NULL;
    }

    p_block = *pp_block;
    *pp_block = NULL;

    for( p = p_block->p_buffer; p < &p_block->p_buffer[p_block->i_buffer]; )
    {
        block_t *p_pic;
        bool b_dummy;
        int i_size = 0;
        int i;

        for( i = 0; i < p_sys->i_avcC_length_size; i++ )
        {
            i_size = (i_size << 8) | (*p++);
        }

        if( i_size <= 0 ||
            i_size > ( p_block->p_buffer + p_block->i_buffer - p ) )
        {
            msg_Err( p_dec, "Broken frame : size %d is too big", i_size );
            break;
        }

        block_t *p_part = CreateAnnexbNAL( p_dec, p, i_size );
        if( !p_part )
            break;

        p_part->i_dts = p_block->i_dts;
        p_part->i_pts = p_block->i_pts;

        /* Parse the NAL */
        if( ( p_pic = ParseNALBlock( p_dec, &b_dummy, p_part ) ) )
        {
            block_ChainAppend( &p_ret, p_pic );
        }
        p += i_size;
    }
    block_Release( p_block );

    return p_ret;
}

/****************************************************************************
 * Helpers
 ****************************************************************************/
static block_t *CreateAnnexbNAL( decoder_t *p_dec, const uint8_t *p, int i_size )
{
    block_t *p_nal;

    p_nal = block_New( p_dec, 4 + i_size );
    if( !p_nal ) return NULL;

    /* Add start code */
    p_nal->p_buffer[0] = 0x00;
    p_nal->p_buffer[1] = 0x00;
    p_nal->p_buffer[2] = 0x00;
    p_nal->p_buffer[3] = 0x01;

    /* Copy nalu */
    memcpy( &p_nal->p_buffer[4], p, i_size );

    VLC_UNUSED(p_dec);
    return p_nal;
}

static void CreateDecodedNAL( uint8_t **pp_ret, int *pi_ret,
                              const uint8_t *src, int i_src )
{
    const uint8_t *end = &src[i_src];
    uint8_t *dst = malloc( i_src );

    *pp_ret = dst;

    if( dst )
    {
        while( src < end )
        {
            if( src < end - 3 && src[0] == 0x00 && src[1] == 0x00 &&
                src[2] == 0x03 )
            {
                *dst++ = 0x00;
                *dst++ = 0x00;

                src += 3;
                continue;
            }
            *dst++ = *src++;
        }
    }
    *pi_ret = dst - *pp_ret;
}

static inline int bs_read_ue( bs_t *s )
{
    int i = 0;

    while( bs_read1( s ) == 0 && s->p < s->p_end && i < 32 )
    {
        i++;
    }
    return( ( 1 << i) - 1 + bs_read( s, i ) );
}

static inline int bs_read_se( bs_t *s )
{
    int val = bs_read_ue( s );

    return val&0x01 ? (val+1)/2 : -(val/2);
}

/*****************************************************************************
 * ParseNALBlock: parses annexB type NALs
 * All p_frag blocks are required to start with 0 0 0 1 4-byte startcode
 *****************************************************************************/
static block_t *ParseNALBlock( decoder_t *p_dec, bool *pb_used_ts, block_t *p_frag )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    block_t *p_pic = NULL;

    const int i_nal_ref_idc = (p_frag->p_buffer[4] >> 5)&0x03;
    const int i_nal_type = p_frag->p_buffer[4]&0x1f;
    const mtime_t i_frag_dts = p_frag->i_dts;
    const mtime_t i_frag_pts = p_frag->i_pts;

    if( p_sys->b_slice && ( !p_sys->b_sps || !p_sys->b_pps ) )
    {
        block_ChainRelease( p_sys->p_frame );
        msg_Warn( p_dec, "waiting for SPS/PPS" );

        /* Reset context */
        p_sys->slice.i_frame_type = 0;
        p_sys->p_frame = NULL;
        p_sys->b_slice = false;
    }

    if( ( !p_sys->b_sps || !p_sys->b_pps ) &&
        i_nal_type >= NAL_SLICE && i_nal_type <= NAL_SLICE_IDR )
    {
        p_sys->b_slice = true;
        /* Fragment will be discarded later on */
    }
    else if( i_nal_type >= NAL_SLICE && i_nal_type <= NAL_SLICE_IDR )
    {
        slice_t slice;
        bool  b_new_picture;

        ParseSlice( p_dec, &b_new_picture, &slice, i_nal_ref_idc, i_nal_type, p_frag );

        /* */
        if( b_new_picture && p_sys->b_slice )
            p_pic = OutputPicture( p_dec );

        /* */
        p_sys->slice = slice;
        p_sys->b_slice = true;
    }
    else if( i_nal_type == NAL_SPS )
    {
        if( p_sys->b_slice )
            p_pic = OutputPicture( p_dec );

        PutSPS( p_dec, p_frag );

        /* Do not append the SPS because we will insert it on keyframes */
        p_frag = NULL;
    }
    else if( i_nal_type == NAL_PPS )
    {
        if( p_sys->b_slice )
            p_pic = OutputPicture( p_dec );

        PutPPS( p_dec, p_frag );

        /* Do not append the PPS because we will insert it on keyframes */
        p_frag = NULL;
    }
    else if( i_nal_type == NAL_AU_DELIMITER ||
             i_nal_type == NAL_SEI ||
             ( i_nal_type >= 13 && i_nal_type <= 18 ) )
    {
        if( p_sys->b_slice )
            p_pic = OutputPicture( p_dec );

        /* TODO parse SEI for CC support */
    }