input.c

vlc stand 0.1.99 ist sehr einfach

    /*
     * Main loop
     */
    intf_DbgMsg("\n");
    while( !p_input->b_die && !p_input->b_error )
    {
        /* Scatter read the UDP packet from the network or the file. */
        if( (input_ReadPacket( p_input )) == (-1) )
        {
            /* FIXME??: Normally, a thread can't kill itself, but we don't have
             * any method in case of an error condition ... */
            p_input->b_error = 1;
        }

#ifdef STATS
        p_input->c_loops++;
#endif
    }

    /*
     * Error loop
     */
    if( p_input->b_error )
    {
        ErrorThread( p_input );
    }

    /* End of thread */
    EndThread( p_input );
    intf_DbgMsg("thread end\n");
}


/*****************************************************************************
 * ErrorThread: RunThread() error loop
 *****************************************************************************
 * This function is called when an error occured during thread main's loop.
 *****************************************************************************/
static void ErrorThread( input_thread_t *p_input )
{
    /* Wait until a `die' order */
    intf_DbgMsg("\n");
    while( !p_input->b_die )
    {
        /* Sleep a while */
        msleep( VOUT_IDLE_SLEEP );
    }
}

/*****************************************************************************
 * EndThread: end the input thread
 *****************************************************************************/
static void EndThread( input_thread_t * p_input )
{
    int *       pi_status;                                  /* threas status */
    int         i_es_loop;                                       /* es index */

    /* Store status */
    intf_DbgMsg("\n");
    pi_status = p_input->pi_status;
    *pi_status = THREAD_END;

    /* Close input method */
    p_input->p_Close( p_input );

    /* Destroy all decoder threads */
    for( i_es_loop = 0;
         (i_es_loop < INPUT_MAX_ES) && (p_input->pp_selected_es[i_es_loop] != NULL) ;
         i_es_loop++ )
    {
        switch( p_input->pp_selected_es[i_es_loop]->i_type )
        {
        case MPEG1_VIDEO_ES:
        case MPEG2_VIDEO_ES:
#ifdef OLD_DECODER
            vdec_DestroyThread( (vdec_thread_t*)(p_input->pp_selected_es[i_es_loop]->p_dec) /*, NULL */ );
#else
            vpar_DestroyThread( (vpar_thread_t*)(p_input->pp_selected_es[i_es_loop]->p_dec) /*, NULL */ );
#endif
            break;
        case MPEG1_AUDIO_ES:
        case MPEG2_AUDIO_ES:
            adec_DestroyThread( (adec_thread_t*)(p_input->pp_selected_es[i_es_loop]->p_dec) );
            break;
        case AC3_AUDIO_ES:
            ac3dec_DestroyThread( (ac3dec_thread_t *)(p_input->pp_selected_es[i_es_loop]->p_dec) );
            break;
        case LPCM_AUDIO_ES:
            lpcmdec_DestroyThread((lpcmdec_thread_t *)(p_input->pp_selected_es[i_es_loop]->p_dec) );
            break;
        case DVD_SPU_ES:
            spudec_DestroyThread( (spudec_thread_t *)(p_input->pp_selected_es[i_es_loop]->p_dec) );
            break;
        case 0:
            /* Special streams for the PSI decoder, PID 0 and 1 */
            break;
#ifdef DEBUG
        default:
            intf_DbgMsg("error: unknown decoder type %d\n", p_input->pp_selected_es[i_es_loop]->i_type );
            break;
#endif
        }
    }

    input_NetlistEnd( p_input );                            /* clean netlist */
    input_PsiEnd( p_input );                        /* clean PSI information */
    input_PcrEnd( p_input );                        /* clean PCR information */
    free( p_input );                          /* free input_thread structure */

    /* Update status */
    *pi_status = THREAD_OVER;
}

/*****************************************************************************
 * input_ReadPacket: reads a packet from the network or the file
 *****************************************************************************/
static __inline__ int input_ReadPacket( input_thread_t *p_input )
{
    int                 i_base_index; /* index of the first free iovec */
    int                 i_current_index;
    int                 i_packet_size;
#ifdef INPUT_LIFO_TS_NETLIST
    int                 i_meanwhile_released;
    int                 i_currently_removed;
#endif
    ts_packet_t *       p_ts_packet;

    /* In this function, we only care about the TS netlist. PES netlist
     * is for the demultiplexer. */
#ifdef INPUT_LIFO_TS_NETLIST
    i_base_index = p_input->netlist.i_ts_index;

    /* Verify that we still have packets in the TS netlist */
    if( (INPUT_MAX_TS + INPUT_TS_READ_ONCE - 1 - p_input->netlist.i_ts_index) <= INPUT_TS_READ_ONCE )
    {
        intf_ErrMsg("input error: TS netlist is empty !\n");
        return( -1 );
    }

#else /* FIFO netlist */
    i_base_index = p_input->netlist.i_ts_start;
    if( p_input->netlist.i_ts_start + INPUT_TS_READ_ONCE -1 > INPUT_MAX_TS )
    {
        /* The netlist is splitted in 2 parts. We must gather them to consolidate
           the FIFO (we make the loop easily in having the same iovec at the far
           end and in the beginning of netlist_free).
           That's why the netlist is (INPUT_MAX_TS +1) + (INPUT_TS_READ_ONCE -1)
           large. */
        memcpy( p_input->netlist.p_ts_free + INPUT_MAX_TS + 1,
                p_input->netlist.p_ts_free,
                (p_input->netlist.i_ts_start + INPUT_TS_READ_ONCE - 1 - INPUT_MAX_TS)
                  * sizeof(struct iovec) );
    }

    /* Verify that we still have packets in the TS netlist */
    if( ((p_input->netlist.i_ts_end -1 - p_input->netlist.i_ts_start) & INPUT_MAX_TS) <= INPUT_TS_READ_ONCE )
    {
        intf_ErrMsg("input error: TS netlist is empty !\n");
        return( -1 );
    }
#endif /* FIFO netlist */

    /* Scatter read the buffer. */
    i_packet_size = (*p_input->p_Read)( p_input,
                           &p_input->netlist.p_ts_free[i_base_index],
                           INPUT_TS_READ_ONCE );
    if( i_packet_size == (-1) )
    {
#if 0
        intf_DbgMsg("Read packet %d %p %d %d\n", i_base_index,
                    &p_input->netlist.p_ts_free[i_base_index],
                    p_input->netlist.i_ts_start,
                    p_input->netlist.i_ts_end);
#endif
        intf_ErrMsg("input error: readv() failed (%s)\n", strerror(errno));
        return( -1 );
    }

    if( i_packet_size == 0 )
    {
        /* No packet has been received, so stop here. */
        return( 0 );
    }

    /* Demultiplex the TS packets (1..INPUT_TS_READ_ONCE) received. */
    for( i_current_index = i_base_index;
         (i_packet_size -= TS_PACKET_SIZE) >= 0;
         i_current_index++ )
    {
        /* BTW, something REALLY bad could happen if we receive packets with
           a wrong size. */
        p_ts_packet = (ts_packet_t*)(p_input->netlist.p_ts_free[i_current_index].iov_base);
        /* Don't cry :-), we are allowed to do that cast, because initially,
           our buffer was malloc'ed with sizeof(ts_packet_t) */

        /* Find out if we need this packet and demultiplex. */
        input_SortPacket( p_input /* for current PIDs and netlist */,
                          p_ts_packet);
    }

    if( i_packet_size > 0 )
    {
        intf_ErrMsg("input error: wrong size\n");
        return( -1 );
    }

    /* Remove the TS packets we have just filled from the netlist */
#ifdef INPUT_LIFO_TS_NETLIST
    /* We need to take a lock here while we're calculating index positions. */
    vlc_mutex_lock( &p_input->netlist.lock );

    i_meanwhile_released = i_base_index - p_input->netlist.i_ts_index;
    if( i_meanwhile_released )
    {
        /* That's where it becomes funny :-). Since we didn't take locks for
           efficiency reasons, other threads (including ourselves, with
           input_DemuxPacket) might have released packets to the netlist.
           So we have to copy these iovec where they should go.

           BTW, that explains why the TS netlist is
           (INPUT_MAX_TS +1) + (TS_READ_ONCE -1) large. */

        i_currently_removed = i_current_index - i_base_index;
        if( i_meanwhile_released < i_currently_removed )
        {
            /* Copy all iovecs in that case */
            memcpy( &p_input->netlist.p_ts_free[p_input->netlist.i_ts_index]
                     + i_currently_removed,
                    &p_input->netlist.p_ts_free[p_input->netlist.i_ts_index],
                    i_meanwhile_released * sizeof(struct iovec) );
        }
        else
        {
            /* We have fewer places than items, so we only move
               i_currently_removed of them. */
            memcpy( &p_input->netlist.p_ts_free[i_base_index],
                    &p_input->netlist.p_ts_free[p_input->netlist.i_ts_index],
                    i_currently_removed * sizeof(struct iovec) );
        }

        /* Update i_netlist_index with the information gathered above. */
        p_input->netlist.i_ts_index += i_currently_removed;
    }
    else
    {
        /* Nothing happened. */
        p_input->netlist.i_ts_index = i_current_index;
    }

    vlc_mutex_unlock( &p_input->netlist.lock );

#else /* FIFO netlist */
    /* & is modulo ; that's where we make the loop. */
    p_input->netlist.i_ts_start = i_current_index & INPUT_MAX_TS;
#endif

#ifdef STATS
    p_input->c_packets_read += i_current_index - i_base_index;
    p_input->c_bytes += (i_current_index - i_base_index) * TS_PACKET_SIZE;
#endif
    return( 0 );
}

/*****************************************************************************
 * input_SortPacket: find out whether we need that packet
 *****************************************************************************/
static __inline__ void input_SortPacket( input_thread_t *p_input,
                                         ts_packet_t *p_ts_packet )
{
    int             i_current_pid;
    int             i_es_loop;

    /* Verify that sync_byte, error_indicator and scrambling_control are
       what we expected. */
    if( !(p_ts_packet->buffer[0] == 0x47) || (p_ts_packet->buffer[1] & 0x80) ||
        (p_ts_packet->buffer[3] & 0xc0) )
    {
        intf_DbgMsg("input debug: invalid TS header (%p)\n", p_ts_packet);
    }
    else
    {
        /* Get the PID of the packet. Note that ntohs is needed, for endianness
           purposes (see man page). */
        i_current_pid = U16_AT(&p_ts_packet->buffer[1]) & 0x1fff;

        //intf_DbgMsg("input debug: pid %d received (%p)\n",
        //            i_current_pid, p_ts_packet);

        /* Lock current ES state. */
        vlc_mutex_lock( &p_input->es_lock );

    /* Verify that we actually want this PID. */
        for( i_es_loop = 0; i_es_loop < INPUT_MAX_SELECTED_ES; i_es_loop++ )
        {
            if( p_input->pp_selected_es[i_es_loop] != NULL)
            {
                if( (*p_input->pp_selected_es[i_es_loop]).i_id
                     == i_current_pid )
                {
                    /* Don't need the lock anymore, since the value pointed
                       out by p_input->pp_selected_es[i_es_loop] can only be
                       modified from inside the input_thread (by the PSI
                       decoder): interface thread is only allowed to modify
                       the pp_selected_es table */
                    vlc_mutex_unlock( &p_input->es_lock );

                    /* We're interested. Pass it to the demultiplexer. */
                    input_DemuxTS( p_input, p_ts_packet,
                                   p_input->pp_selected_es[i_es_loop] );
                    return;
                }
            }
            else
            {
                /* pp_selected_es should not contain any hole. */
                break;
            }
        }
        vlc_mutex_unlock( &p_input->es_lock );
    }

    /* We weren't interested in receiving this packet. Give it back to the
       netlist. */
    //intf_DbgMsg("SortPacket: freeing unwanted TS %p (pid %d)\n", p_ts_packet,
    //                 U16_AT(&p_ts_packet->buffer[1]) & 0x1fff);
    input_NetlistFreeTS( p_input, p_ts_packet );
#ifdef STATS
    p_input->c_packets_trashed++;
#endif
}

/*****************************************************************************
 * input_DemuxTS: first step of demultiplexing: the TS header
 *****************************************************************************
 * Stream must also only contain PES and PSI, so PID must have been filtered
 *****************************************************************************/
static __inline__ void input_DemuxTS( input_thread_t *p_input,
                                      ts_packet_t *p_ts_packet,
                                      es_descriptor_t *p_es_descriptor )
{
    int         i_dummy;
    boolean_t   b_adaption;                     /* Adaption field is present */
    boolean_t   b_payload;                         /* Packet carries payload */
    boolean_t   b_unit_start;          /* A PSI or a PES start in the packet */
    boolean_t   b_trash = 0;                 /* Must the packet be trashed ? */
    boolean_t   b_lost = 0;                     /* Was there a packet lost ? */

    ASSERT(p_input);
    ASSERT(p_ts_packet);
    ASSERT(p_es_descriptor);

#define p (p_ts_packet->buffer)

    //intf_DbgMsg("input debug: TS-demultiplexing packet %p, pid %d, number %d\n",
    //            p_ts_packet, U16_AT(&p[1]) & 0x1fff, p[3] & 0x0f);

#ifdef STATS
    p_es_descriptor->c_packets++;
    p_es_descriptor->c_bytes += TS_PACKET_SIZE;
#endif