h264.c

video linux conference

/*****************************************************************************
 * h264.c: h264/avc video packetizer
 *****************************************************************************
 * Copyright (C) 2001, 2002 VideoLAN
 * $Id: h264.c 10783 2005-04-23 22:37:22Z sigmunau $
 *
 * Authors: Laurent Aimar <[e-mail]>
 *          Eric Petit <[e-mail]>
 *          Gildas Bazin <[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 <stdlib.h>                                      /* malloc(), free() */

#include <vlc/vlc.h>
#include <vlc/decoder.h>
#include <vlc/sout.h>

#include "vlc_block_helper.h"
#include "vlc_bits.h"

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
static int  Open ( vlc_object_t * );
static void Close( vlc_object_t * );

vlc_module_begin();
    set_category( CAT_SOUT );
    set_subcategory( SUBCAT_SOUT_PACKETIZER );
    set_description( _("H264 video packetizer") );
    set_capability( "packetizer", 50 );
    set_callbacks( Open, Close );
vlc_module_end();


/****************************************************************************
 * Local prototypes
 ****************************************************************************/
static block_t *Packetize( decoder_t *, block_t ** );
static block_t *PacketizeAVC1( decoder_t *, block_t ** );

struct decoder_sys_t
{
    block_bytestream_t bytestream;

    int     i_state;
    int     i_offset;
    uint8_t startcode[4];

    vlc_bool_t b_slice;
    block_t    *p_frame;

    vlc_bool_t   b_sps;
    vlc_bool_t   b_pps;

    /* avcC data */
    int i_avcC_length_size;

    /* Useful values of the Sequence Parameter Set */
    int i_log2_max_frame_num;
    int b_frame_mbs_only;

    /* Useful values of the Slice Header */
    int i_nal_type;
    int i_nal_ref_idc;
    int i_idr_pic_id;
    int i_frame_num;
};

enum
{
    STATE_NOSYNC,
    STATE_NEXT_SYNC,
};

enum nal_unit_type_e
{
    NAL_UNKNOWN = 0,
    NAL_SLICE   = 1,
    NAL_SLICE_DPA   = 2,
    NAL_SLICE_DPB   = 3,
    NAL_SLICE_DPC   = 4,
    NAL_SLICE_IDR   = 5,    /* ref_idc != 0 */
    NAL_SEI         = 6,    /* ref_idc == 0 */
    NAL_SPS         = 7,
    NAL_PPS         = 8,
    NAL_AU_DELIMITER= 9
    /* ref_idc == 0 for 6,9,10,11,12 */
};

enum nal_priority_e
{
    NAL_PRIORITY_DISPOSABLE = 0,
    NAL_PRIORITY_LOW        = 1,
    NAL_PRIORITY_HIGH       = 2,
    NAL_PRIORITY_HIGHEST    = 3,
};

static block_t *ParseNALBlock( decoder_t *, block_t * );

static block_t *nal_get_annexeb( decoder_t *, uint8_t *p, int );

/*****************************************************************************
 * Open: probe the packetizer and return score
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    decoder_t     *p_dec = (decoder_t*)p_this;
    decoder_sys_t *p_sys;

    if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'h', '2', '6', '4') &&
        p_dec->fmt_in.i_codec != VLC_FOURCC( 'H', '2', '6', '4') &&
        p_dec->fmt_in.i_codec != VLC_FOURCC( 'V', 'S', 'S', 'H') &&
        p_dec->fmt_in.i_codec != VLC_FOURCC( 'v', 's', 's', 'h') &&
        ( p_dec->fmt_in.i_codec != VLC_FOURCC( 'a', 'v', 'c', '1') ||
          p_dec->fmt_in.i_extra < 7 ) )
    {
        return VLC_EGENERIC;
    }

    /* Allocate the memory needed to store the decoder's structure */
    if( ( p_dec->p_sys = p_sys = malloc( sizeof(decoder_sys_t) ) ) == NULL )
    {
        msg_Err( p_dec, "out of memory" );
        return VLC_EGENERIC;
    }
    p_sys->i_state = STATE_NOSYNC;
    p_sys->i_offset = 0;
    p_sys->startcode[0] = 0;
    p_sys->startcode[1] = 0;
    p_sys->startcode[2] = 0;
    p_sys->startcode[3] = 1;
    p_sys->bytestream = block_BytestreamInit( p_dec );
    p_sys->b_slice = VLC_FALSE;
    p_sys->p_frame = NULL;
    p_sys->b_sps   = VLC_FALSE;
    p_sys->b_pps   = VLC_FALSE;

    p_sys->i_nal_type = -1;
    p_sys->i_nal_ref_idc = -1;
    p_sys->i_idr_pic_id = -1;
    p_sys->i_frame_num = -1;

    /* Setup properties */
    es_format_Copy( &p_dec->fmt_out, &p_dec->fmt_in );
    p_dec->fmt_out.i_codec = VLC_FOURCC( 'h', '2', '6', '4' );
    /* FIXME: FFMPEG isn't happy at all if you leave this */
    if( p_dec->fmt_out.i_extra ) free( p_dec->fmt_out.p_extra );
    p_dec->fmt_out.i_extra = 0; p_dec->fmt_out.p_extra = 0;

    if( p_dec->fmt_in.i_codec == VLC_FOURCC( 'a', 'v', 'c', '1' ) )
    {
        uint8_t *p = &((uint8_t*)p_dec->fmt_in.p_extra)[4];
        int i_sps, i_pps;
        int i;

        /* Parse avcC */
        p_sys->i_avcC_length_size = 1 + ((*p++)&0x03);

        /* Read SPS */
        i_sps = (*p++)&0x1f;

        for( i = 0; i < i_sps; i++ )
        {
            int i_length = GetWBE( p );
            block_t *p_sps = nal_get_annexeb( p_dec, p + 2, i_length );

            ParseNALBlock( p_dec, p_sps );
            p += 2 + i_length;
        }
        /* Read PPS */
        i_pps = *p++;
        for( i = 0; i < i_pps; i++ )
        {
            int i_length = GetWBE( p );
            block_t *p_pps = nal_get_annexeb( p_dec, p + 2, i_length );

            ParseNALBlock( p_dec, p_pps );
            p += 2 + i_length;
        }
        msg_Dbg( p_dec, "avcC length size=%d sps=%d pps=%d",
                 p_sys->i_avcC_length_size, i_sps, i_pps );

        /* Set callback */
        p_dec->pf_packetize = PacketizeAVC1;
    }
    else
    {
        /* Set callback */
        p_dec->pf_packetize = Packetize;
    }

    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;

    block_BytestreamRelease( &p_sys->bytestream );
    free( p_sys );
}

/****************************************************************************
 * Packetize: the whole thing
 ****************************************************************************/
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;

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

    for( ;; )
    {
        switch( p_sys->i_state )
        {
            case STATE_NOSYNC:
                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 )
                {
                    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 startcode */
                if( block_FindStartcodeFromOffset( &p_sys->bytestream,
                      &p_sys->i_offset, p_sys->startcode, 3 ) != VLC_SUCCESS)
                {
                    if( block_FindStartcodeFromOffset( &p_sys->bytestream,
                          &p_sys->i_offset, p_sys->startcode+1, 3 ) !=
                        VLC_SUCCESS )
                    {
                        /* Need more data */
                        return NULL;
                    }
                }

                /* Get the new fragment and set the pts/dts */
                p_pic = block_New( p_dec, p_sys->i_offset );
                p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
                p_pic->i_dts = p_sys->bytestream.p_block->i_dts;

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

                p_sys->i_offset = 0;

                /* Parse the NAL */
                if( !( p_pic = ParseNALBlock( p_dec, p_pic ) ) )
                {
                    p_sys->i_state = STATE_NOSYNC;
                    break;
                }
#if 0
                msg_Dbg( p_dec, "pts="I64Fd" dts="I64Fd,
                         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: the whole thing
 ****************************************************************************/
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;

    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;
        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 )
        {
            block_t *p_part = nal_get_annexeb( p_dec, p, i_size );

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