[vlc-devel] [PATCH] rtp: JPEG packetization

[Rémi Denis-Courmont]

Please keep variables scope to a minimum in new code.
VLC ois not ANSI C anymore.

Le dimanche 30 septembre 2012 00:41:50, Samuel Pitoiset a écrit :
> ---
>  modules/stream_out/rtpfmt.c | 117
> +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 116
> insertions(+), 1 deletion(-)
> 
> diff --git a/modules/stream_out/rtpfmt.c b/modules/stream_out/rtpfmt.c
> index 79ae441..1de82c0 100644
> --- a/modules/stream_out/rtpfmt.c
> +++ b/modules/stream_out/rtpfmt.c
> @@ -53,6 +53,7 @@ static int rtp_packetize_g726_24 (sout_stream_id_t *,
> block_t *); static int rtp_packetize_g726_32 (sout_stream_id_t *, block_t
> *); static int rtp_packetize_g726_40 (sout_stream_id_t *, block_t *);
> static int rtp_packetize_xiph (sout_stream_id_t *, block_t *);
> +static int rtp_packetize_jpeg (sout_stream_id_t *, block_t *);
> 
>  #define XIPH_IDENT (0)
> 
> @@ -511,7 +512,11 @@ int rtp_get_fmt( vlc_object_t *obj, es_format_t
> *p_fmt, const char *mux, rtp_fmt->clock_rate = 1000;
>              rtp_fmt->pf_packetize = rtp_packetize_t140;
>              break;
> -
> +        case VLC_CODEC_MJPG:
> +            rtp_fmt->payload_type = 26;
> +            rtp_fmt->ptname = "JPEG";
> +            rtp_fmt->pf_packetize = rtp_packetize_jpeg;
> +            break;
>          default:
>              msg_Err( obj, "cannot add this stream (unsupported "
>                       "codec: %4.4s)", (char*)&p_fmt->i_codec );
> @@ -660,6 +665,116 @@ static int rtp_packetize_xiph( sout_stream_id_t *id,
> block_t *in ) return VLC_SUCCESS;
>  }
> 
> +/* rfc2435 */
> +static int rtp_packetize_jpeg( sout_stream_id_t *id, block_t *in )
> +{
> +    uint8_t       *p_data      = in->p_buffer;
> +    int           i_data       = in->i_buffer;
> +    uint32_t      i_off        = 0; /* fragment offset of the current
> frame */ +    int           i_nb_qtables = 0;
> +    int           i_packet     = 0;
> +    const uint8_t *p_qtables   = NULL;
> +    uint8_t       w            = 0;
> +    uint8_t       h            = 0;
> +    int           i;
> +
> +    /* preparse the header for getting some infos */
> +    for( i = 0; i < i_data; i++ )
> +    {
> +        if( p_data[i] != 0xff )
> +            continue;
> +
> +        if( p_data[i + 1] == 0xdb ) // DQT
> +        {
> +            /* a quantization table is 64 bytes long */
> +            i_nb_qtables = GetWBE( &p_data[i + 2] ) / 65;
> +            if( i + 4 + i_nb_qtables * 65 > i_data )
> +            {
> +                fprintf( stderr, "Too short JPEG header. Aborted!\n" );
> +                return VLC_EGENERIC;
> +            }
> +
> +            p_qtables = &p_data[i + 4];
> +        }
> +        else if( p_data[i + 1] == 0xc0 ) // SOF0
> +        {
> +            if( p_data[i + 14] != 17 || p_data[i + 17] != 17 )
> +            {
> +                fprintf( stderr,
> +                         "Only 1x1 chroma blocks are supported.
> Aborted!\n" ); +                return VLC_EGENERIC;
> +            }
> +
> +            /* convert video pixel dimensions from pixels to blocks */
> +            h = GetWBE( &p_data[i + 5] ) >> 3;
> +            w = GetWBE( &p_data[i + 7] ) >> 3;
> +        }
> +        else if( p_data[i + 1] == 0xda ) // SOS
> +        {
> +            /* SOS is last marker in the header */
> +            i += GetWBE( &p_data[i + 2] ) + 2;
> +            break;
> +        }
> +    }
> +
> +    if( w == 0 || h == 0 )
> +    {
> +        fprintf( stderr, "Cannot find video pixel dimensions. Aborted!\n"
> ); +        return VLC_EGENERIC;
> +    }
> +
> +    /* skip JPEG header */
> +    p_data += i;
> +    i_data -= i;
> +
> +    while( i_data > 0 )
> +    {
> +        int i_hdr_size = 8;
> +
> +        if( i_off == 0 && i_nb_qtables )
> +            i_hdr_size += 4 + 64 * i_nb_qtables;
> +
> +        /* payload max in one packet */
> +        int i_max     = rtp_mtu (id) - i_hdr_size;
> +        int i_count   = ( in->i_buffer + i_max - 1 ) / i_max;
> +        int i_payload = __MIN( i_max, i_data );
> +        block_t *out  = block_Alloc( 12 + i_hdr_size + i_payload );
> +
> +        /* rtp common header */
> +        rtp_packetize_common( id, out, i_data == i_payload, in->i_dts );
> +
> +        /* Type-specific:8, Fragment Offset:24, Type:8, Q:8, Width:8,
> Height:8 */ +        uint64_t header = ((uint64_t)0 << 56) |
> ((uint64_t)i_off << 32) | +                          (1 << 24) | (255 <<
> 16) | (w << 8) | h; +        SetQWBE( out->p_buffer + 12, header );
> +
> +        if( i_off == 0 && i_nb_qtables )
> +        {
> +            uint32_t header = (0 << 24) | (0 << 16) | 64 * i_nb_qtables;
> +            SetDWBE( out->p_buffer + 20, header );
> +
> +            for( i = 0; i < i_nb_qtables; i++ )
> +                memcpy( &out->p_buffer[24 + 64 * i], &p_qtables[65 * i +
> 1], 64 ); +        }
> +
> +        /* copy payload data */
> +        memcpy( &out->p_buffer[12 + i_hdr_size], p_data, i_payload );
> +
> +        out->i_buffer = 12 + i_hdr_size + i_payload;
> +        out->i_dts    = in->i_dts + i_packet++ * in->i_length / i_count;
> +        out->i_length = in->i_length / i_count;
> +
> +        /* send the RTP/JPEG packet */
> +        rtp_packetize_send( id, out );
> +
> +        p_data += i_payload;
> +        i_data -= i_payload;
> +        i_off  += i_payload;
> +    }
> +
> +    return VLC_SUCCESS;
> +}
> +
>  static int rtp_packetize_mpa( sout_stream_id_t *id, block_t *in )
>  {
>      int     i_max   = rtp_mtu (id) - 4; /* payload max in one packet */

-- 
Rémi Denis-Courmont
http://www.remlab.net/