video_output.c

video linux conference

    picture_t *     p_picture;                            /* picture pointer */
    picture_t *     p_last_picture = NULL;                   /* last picture */
    picture_t *     p_directbuffer;              /* direct buffer to display */

    subpicture_t *  p_subpic;                          /* subpicture pointer */

    /*
     * Initialize thread
     */
    p_vout->b_error = InitThread( p_vout );

    /* signal the creation of the vout */
    vlc_thread_ready( p_vout );

    if( p_vout->b_error )
    {
        /* Destroy thread structures allocated by Create and InitThread */
        DestroyThread( p_vout );
        return;
    }

    /*
     * Main loop - it is not executed if an error occurred during
     * initialization
     */
    while( (!p_vout->b_die) && (!p_vout->b_error) )
    {
        /* Initialize loop variables */
        p_picture = NULL;
        display_date = 0;
        current_date = mdate();

#if 0
        p_vout->c_loops++;
        if( !(p_vout->c_loops % VOUT_STATS_NB_LOOPS) )
        {
            msg_Dbg( p_vout, "picture heap: %d/%d",
                     I_RENDERPICTURES, p_vout->i_heap_size );
        }
#endif

        /*
         * Find the picture to display (the one with the earliest date).
         * This operation does not need lock, since only READY_PICTUREs
         * are handled. */
        for( i_index = 0; i_index < I_RENDERPICTURES; i_index++ )
        {
            if( (PP_RENDERPICTURE[i_index]->i_status == READY_PICTURE)
                && ( (p_picture == NULL) ||
                     (PP_RENDERPICTURE[i_index]->date < display_date) ) )
            {
                p_picture = PP_RENDERPICTURE[i_index];
                display_date = p_picture->date;
            }
        }

        if( p_picture )
        {
            /* If we met the last picture, parse again to see whether there is
             * a more appropriate one. */
            if( p_picture == p_last_picture )
            {
                for( i_index = 0; i_index < I_RENDERPICTURES; i_index++ )
                {
                    if( (PP_RENDERPICTURE[i_index]->i_status == READY_PICTURE)
                        && (PP_RENDERPICTURE[i_index] != p_last_picture)
                        && ((p_picture == p_last_picture) ||
                            (PP_RENDERPICTURE[i_index]->date < display_date)) )
                    {
                        p_picture = PP_RENDERPICTURE[i_index];
                        display_date = p_picture->date;
                    }
                }
            }

            /* If we found better than the last picture, destroy it */
            if( p_last_picture && p_picture != p_last_picture )
            {
                vlc_mutex_lock( &p_vout->picture_lock );
                if( p_last_picture->i_refcount )
                {
                    p_last_picture->i_status = DISPLAYED_PICTURE;
                }
                else
                {
                    p_last_picture->i_status = DESTROYED_PICTURE;
                    p_vout->i_heap_size--;
                }
                vlc_mutex_unlock( &p_vout->picture_lock );
                p_last_picture = NULL;
            }

            /* Compute FPS rate */
            p_vout->p_fps_sample[ p_vout->c_fps_samples++ % VOUT_FPS_SAMPLES ]
                = display_date;

            if( !p_picture->b_force &&
                p_picture != p_last_picture &&
                display_date < current_date + p_vout->render_time )
            {
                /* Picture is late: it will be destroyed and the thread
                 * will directly choose the next picture */
                vlc_mutex_lock( &p_vout->picture_lock );
                if( p_picture->i_refcount )
                {
                    /* Pretend we displayed the picture, but don't destroy
                     * it since the decoder might still need it. */
                    p_picture->i_status = DISPLAYED_PICTURE;
                }
                else
                {
                    /* Destroy the picture without displaying it */
                    p_picture->i_status = DESTROYED_PICTURE;
                    p_vout->i_heap_size--;
                }
                msg_Warn( p_vout, "late picture skipped ("I64Fd")",
                                  current_date - display_date );
                vlc_mutex_unlock( &p_vout->picture_lock );

                continue;
            }

            if( display_date >
                current_date + p_vout->i_pts_delay + VOUT_BOGUS_DELAY )
            {
                /* Picture is waaay too early: it will be destroyed */
                vlc_mutex_lock( &p_vout->picture_lock );
                if( p_picture->i_refcount )
                {
                    /* Pretend we displayed the picture, but don't destroy
                     * it since the decoder might still need it. */
                    p_picture->i_status = DISPLAYED_PICTURE;
                }
                else
                {
                    /* Destroy the picture without displaying it */
                    p_picture->i_status = DESTROYED_PICTURE;
                    p_vout->i_heap_size--;
                }
                msg_Warn( p_vout, "vout warning: early picture skipped "
                          "("I64Fd")", display_date - current_date
                          - p_vout->i_pts_delay );
                vlc_mutex_unlock( &p_vout->picture_lock );

                continue;
            }

            if( display_date > current_date + VOUT_DISPLAY_DELAY )
            {
                /* A picture is ready to be rendered, but its rendering date
                 * is far from the current one so the thread will perform an
                 * empty loop as if no picture were found. The picture state
                 * is unchanged */
                p_picture    = NULL;
                display_date = 0;
            }
            else if( p_picture == p_last_picture )
            {
                /* We are asked to repeat the previous picture, but we first
                 * wait for a couple of idle loops */
                if( i_idle_loops < 4 )
                {
                    p_picture    = NULL;
                    display_date = 0;
                }
                else
                {
                    /* We set the display date to something high, otherwise
                     * we'll have lots of problems with late pictures */
                    display_date = current_date + p_vout->render_time;
                }
            }
        }

        if( p_picture == NULL )
        {
            i_idle_loops++;
        }

        if( p_picture && p_vout->b_snapshot )
        {
            p_vout->b_snapshot = VLC_FALSE;
            vout_Snapshot( p_vout, p_picture );
        }

        /*
         * Check for subpictures to display
         */
        p_subpic = spu_SortSubpictures( p_vout->p_spu, display_date );

        /*
         * Perform rendering
         */
        p_directbuffer = vout_RenderPicture( p_vout, p_picture, p_subpic );

        /*
         * Call the plugin-specific rendering method if there is one
         */
        if( p_picture != NULL && p_directbuffer != NULL && p_vout->pf_render )
        {
            /* Render the direct buffer returned by vout_RenderPicture */
            p_vout->pf_render( p_vout, p_directbuffer );
        }

        /*
         * Sleep, wake up
         */
        if( display_date != 0 && p_directbuffer != NULL )
        {
            mtime_t current_render_time = mdate() - current_date;
            /* if render time is very large we don't include it in the mean */
            if( current_render_time < p_vout->render_time +
                VOUT_DISPLAY_DELAY )
            {
                /* Store render time using a sliding mean weighting to
                 * current value in a 3 to 1 ratio*/
                p_vout->render_time *= 3;
                p_vout->render_time += current_render_time;
                p_vout->render_time >>= 2;
            }
        }

        /* Give back change lock */
        vlc_mutex_unlock( &p_vout->change_lock );

        /* Sleep a while or until a given date */
        if( display_date != 0 )
        {
            /* If there are filters in the chain, better give them the picture
             * in advance */
            if( !p_vout->psz_filter_chain || !*p_vout->psz_filter_chain )
            {
                mwait( display_date - VOUT_MWAIT_TOLERANCE );
            }
        }
        else
        {
            msleep( VOUT_IDLE_SLEEP );
        }

        /* On awakening, take back lock and send immediately picture
         * to display. */
        vlc_mutex_lock( &p_vout->change_lock );

        /*
         * Display the previously rendered picture
         */
        if( p_picture != NULL && p_directbuffer != NULL )
        {
            /* Display the direct buffer returned by vout_RenderPicture */
            if( p_vout->pf_display )
            {
                p_vout->pf_display( p_vout, p_directbuffer );
            }

            /* Tell the vout this was the last picture and that it does not
             * need to be forced anymore. */
            p_last_picture = p_picture;
            p_last_picture->b_force = 0;
        }

        if( p_picture != NULL )
        {
            /* Reinitialize idle loop count */
            i_idle_loops = 0;
        }

        /*
         * Check events and manage thread
         */
        if( p_vout->pf_manage && p_vout->pf_manage( p_vout ) )
        {
            /* A fatal error occurred, and the thread must terminate
             * immediately, without displaying anything - setting b_error to 1
             * causes the immediate end of the main while() loop. */
            p_vout->b_error = 1;
        }

        if( p_vout->i_changes & VOUT_SIZE_CHANGE )
        {
            /* this must only happen when the vout plugin is incapable of
             * rescaling the picture itself. In this case we need to destroy
             * the current picture buffers and recreate new ones with the right
             * dimensions */
            int i;

            p_vout->i_changes &= ~VOUT_SIZE_CHANGE;

            p_vout->pf_end( p_vout );
            for( i = 0; i < I_OUTPUTPICTURES; i++ )
                 p_vout->p_picture[ i ].i_status = FREE_PICTURE;

            I_OUTPUTPICTURES = 0;
            if( p_vout->pf_init( p_vout ) )
            {
                msg_Err( p_vout, "cannot resize display" );
                /* FIXME: pf_end will be called again in EndThread() */
                p_vout->b_error = 1;
            }

            /* Need to reinitialise the chroma plugin */
            if( p_vout->chroma.p_module )
            {
                if( p_vout->chroma.p_module->pf_deactivate )
                    p_vout->chroma.p_module->pf_deactivate( VLC_OBJECT(p_vout) );
                p_vout->chroma.p_module->pf_activate( VLC_OBJECT(p_vout) );
            }
        }

        if( p_vout->i_changes & VOUT_PICTURE_BUFFERS_CHANGE )
        {
            /* This happens when the picture buffers need to be recreated.
             * This is useful on multimonitor displays for instance.
             *
             * Warning: This only works when the vout creates only 1 picture
             * buffer!! */
            p_vout->i_changes &= ~VOUT_PICTURE_BUFFERS_CHANGE;

            if( !p_vout->b_direct )
            {
                module_Unneed( p_vout, p_vout->chroma.p_module );
            }

            vlc_mutex_lock( &p_vout->picture_lock );

            p_vout->pf_end( p_vout );

            I_OUTPUTPICTURES = I_RENDERPICTURES = 0;

            p_vout->b_error = InitThread( p_vout );

            vlc_mutex_unlock( &p_vout->picture_lock );
        }
    }

    /*
     * Error loop - wait until the thread destruction is requested
     */
    if( p_vout->b_error )
    {
        ErrorThread( p_vout );
    }

    /* End of thread */
    EndThread( p_vout );

    /* Destroy thread structures allocated by CreateThread */
    DestroyThread( p_vout );
}

/*****************************************************************************
 * ErrorThread: RunThread() error loop
 *****************************************************************************
 * This function is called when an error occurred during thread main's loop.
 * The thread can still receive feed, but must be ready to terminate as soon
 * as possible.
 *****************************************************************************/
static void ErrorThread( vout_thread_t *p_vout )
{
    /* Wait until a `die' order */
    while( !p_vout->b_die )
    {
        /* Sleep a while */
        msleep( VOUT_IDLE_SLEEP );
    }
}

/*****************************************************************************
 * EndThread: thread destruction