peakmeter.c

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 * @param int range_max - Specifies the upper value of the range. 
 *                        Pass a value dBfs * 100 when dbfs is set to true.
 *                        Pass a percent value when dbfs is set to false.
 */
void peak_meter_init_range( bool dbfs, int range_min, int range_max) {
    peak_meter_use_dbfs = dbfs;
    peak_meter_set_min(range_min);
    peak_meter_set_max(range_max);
}

/**
 * Initialize the peak meter with all relevant values concerning times.
 * @param int release - Set the maximum amount of pixels the meter is allowed
 *                      to decrease with each redraw
 * @param int hold - Select the time preset for the time the peak indicator 
 *                   is reset after a peak occurred. The preset values are 
 *                   stored in max_time_out.
 * @param int clip_hold - Select the time preset for the time the peak 
 *                        indicator is reset after a peak occurred. The preset 
 *                        values are stored in clip_time_out.
 */
void peak_meter_init_times(int release, int hold, int clip_hold) {
    peak_meter_hold = hold;
    peak_meter_release = release;
    peak_meter_clip_hold = clip_hold;
}

/**
 * Set the source of the peak meter to playback or to 
 * record.
 * @param: bool playback - If true playback peak meter is used.
 *         If false recording peak meter is used.
 */
void peak_meter_playback(bool playback) {
#ifdef SIMULATOR
    (void)playback;
#else
    if (playback) {
        peak_meter_src_l = MAS_REG_DQPEAK_L;
        peak_meter_src_r = MAS_REG_DQPEAK_R;
    } else {
        peak_meter_src_l = MAS_REG_QPEAK_L;
        peak_meter_src_r = MAS_REG_QPEAK_R;
    }
#endif
}

/**
 * Reads peak values from the MAS, and detects clips. The 
 * values are stored in peak_meter_l peak_meter_r for later 
 * evauluation. Consecutive calls to peak_meter_peek detect 
 * that ocurred. This function could be used by a thread for
 * busy reading the MAS.
 */
inline void peak_meter_peek(void) {
#ifdef SIMULATOR
    int left = 8000;
    int right = 9000;
#else
   /* read the peak values */
    int left  = mas_codec_readreg(peak_meter_src_l);
    int right = mas_codec_readreg(peak_meter_src_r);
#endif

    /* check for clips
       An clip is assumed when two consecutive readouts
       of the volume are at full scale. This is proven
       to be inaccurate in both ways: it may detect clips
       when no clip occurred and it may fail to detect
       a real clip. */
    if ((left  == peak_meter_l) && 
        (left  == MAX_PEAK - 1)) {
        peak_meter_l_clip = true;
        peak_meter_clip_timeout_l = 
            current_tick + clip_time_out[peak_meter_clip_hold];
    }

    if ((right == peak_meter_r) && 
        (right == MAX_PEAK - 1)) {
        peak_meter_r_clip = true;
        peak_meter_clip_timeout_r = 
            current_tick + clip_time_out[peak_meter_clip_hold];
    }

    /* peaks are searched -> we have to find the maximum. When
       many calls of peak_meter_peek the maximum value will be
       stored in peak_meter_x. This maximum is reset by the
       functions peak_meter_read_x. */
    peak_meter_l = MAX(peak_meter_l, left);
    peak_meter_r = MAX(peak_meter_r, right);

#ifdef PM_DEBUG
    peek_calls++;
#endif
}


/**
 * The thread function for the peak meter calls peak_meter_peek 
 * to reas out the mas and find maxima, clips, etc. No display
 * is performed.
 */
/*
void peak_meter_thread(void) {
    sleep(5000);
    while (1) {
        if (peak_meter_enabled && peak_meter_use_thread){
            peak_meter_peek();
        }
        yield();
    }
}
*/

/**
 * Creates the peak meter thread 
 */
/*
void peak_meter_init(void) {
    create_thread(
        peak_meter_thread, 
        peak_meter_stack, 
        sizeof peak_meter_stack, 
        "peakmeter");
}
*/

/**
 * Reads out the peak volume of the left channel.
 * @return int - The maximum value that has been detected
 * since the last call of peak_meter_read_l. The value
 * is in the range 0 <= value < MAX_PEAK.
 */
static int peak_meter_read_l (void) {
    /* peak_meter_l contains the maximum of
       all peak values that were read by peak_meter_peek 
       since the last call of peak_meter_read_r */
    int retval = peak_meter_l;
#ifdef PM_DEBUG
    peek_calls = 0;
#endif

#ifdef SIMULATOR
    peak_meter_l = 8000;
#else
    /* reset peak_meter_l so that subsequent calls of
       peak_meter_peek doesn't get fooled by an old
       maximum value */
    peak_meter_l = mas_codec_readreg(peak_meter_src_l);
#endif
    return retval;
}

/**
 * Reads out the peak volume of the right channel.
 * @return int - The maximum value that has been detected
 * since the last call of peak_meter_read_l. The value
 * is in the range 0 <= value < MAX_PEAK.
 */
static int peak_meter_read_r (void) {
    /* peak_meter_r contains the maximum of
       all peak values that were read by peak_meter_peek 
       since the last call of peak_meter_read_r */
    int retval = peak_meter_r;
#ifdef PM_DEBUG
    peek_calls = 0;
#endif

#ifdef SIMULATOR
    peak_meter_l = 8000;
#else
    /* reset peak_meter_r so that subsequent calls of
       peak_meter_peek doesn't get fooled by an old
       maximum value */
    peak_meter_r = mas_codec_readreg(peak_meter_src_r);
#endif
    return retval;
}

/**
 * Reset the detected clips. This method is for
 * use by the user interface.
 * @param int unused - This parameter was added to
 * make the function compatible with set_int
 */
void peak_meter_set_clip_hold(int time) {
    peak_meter_clip_eternal = false;

    if (time <= 0) {
        peak_meter_l_clip = false;
        peak_meter_r_clip = false;
        peak_meter_clip_eternal = true;
    }
}

/**
 * Scales a peak value as read from the MAS to the range of meterwidth.
 * The scaling is performed according to the scaling method (dBfs / linear)
 * and the range (peak_meter_range_min .. peak_meter_range_max).
 * @param unsigned short val - The volume value. Range: 0 <= val < MAX_PEAK
 * @param int meterwidht - The widht of the meter in pixel
 * @return unsigned short - A value 0 <= return value <= meterwidth
 */
unsigned short peak_meter_scale_value(unsigned short val, int meterwidth){
    int retval;

    if (val <= peak_meter_range_min) {
        return 0;
    }

    if (val >= peak_meter_range_max) {
        return meterwidth;
    }

    retval = val;

    /* different scaling is used for dBfs and linear percent */
    if (peak_meter_use_dbfs) {

        /* scale the samples dBfs */
        retval  = (calc_db(retval) - db_min) * meterwidth / db_range;
    }

    /* Scale for linear percent display */
    else
    {
        /* scale the samples */
        retval  = ((retval - peak_meter_range_min) * meterwidth) 
                  / peak_meter_range;
    }
    return retval;
}


/**
 * Draws a peak meter in the specified size at the specified position.
 * @param int x - The x coordinate. 
 *                Make sure that 0 <= x and x + width < LCD_WIDTH
 * @param int y - The y coordinate. 
 *                Make sure that 0 <= y and y + height < LCD_HEIGHT
 * @param int width - The width of the peak meter. Note that for display
 *                    of clips a 3 pixel wide area is used ->
 *                    width > 3
 * @param int height - The height of the peak meter. height > 3
 */
void peak_meter_draw(int x, int y, int width, int height) {
    int left = 0, right = 0;
    static int last_left = 0, last_right = 0;
    int meterwidth = width - 3;
    int i;

#ifdef PM_DEBUG
    static long pm_tick = 0;
    int tmp = peek_calls;
#endif

    /* if disabled only draw the peak meter */
    if (peak_meter_enabled) {

        /* read the volume info from MAS */
        left  = peak_meter_read_l(); 
        right = peak_meter_read_r(); 
        /*peak_meter_peek();*/

        /* scale the samples dBfs */
        left  = peak_meter_scale_value(left, meterwidth);
        right = peak_meter_scale_value(right, meterwidth);
    
        /* if the scale has changed -> recalculate the scale 
           (The scale becomes invalid when the range changed.) */
        if (!db_scale_valid){

            if (peak_meter_use_dbfs) {
                db_scale_count = DB_SCALE_SRC_VALUES_SIZE;
                for (i = 0; i < db_scale_count; i++){
                    /* find the real x-coords for predefined interesting
                       dBfs values. These only are recalculated when the
                       scaling of the meter changed. */
                        db_scale_lcd_coord[i] = 
                            peak_meter_scale_value(
                                db_scale_src_values[i], 
                                meterwidth - 1);
                } 
            }

            /* when scaling linear we simly make 10% steps */
            else {
                db_scale_count = 10;
                for (i = 0; i < db_scale_count; i++) {
                    db_scale_lcd_coord[i] = 
                        (i * (MAX_PEAK / 10) - peak_meter_range_min) *
                        meterwidth / peak_meter_range;
                }
            }

            /* mark scale valid to avoid recalculating dBfs values
               of the scale. */
            db_scale_valid = true;
        }

        /* apply release */
        left  = MAX(left , last_left  - peak_meter_release);
        right = MAX(right, last_right - peak_meter_release);

        /* reset max values after timeout */
        if (TIME_AFTER(current_tick, peak_meter_timeout_l)){
            peak_meter_max_l = 0;
        }

        if (TIME_AFTER(current_tick, peak_meter_timeout_r)){
            peak_meter_max_r = 0;
        }

        if (!peak_meter_clip_eternal) {
            if (peak_meter_l_clip && 
                TIME_AFTER(current_tick, peak_meter_clip_timeout_l)){
                peak_meter_l_clip = false;
            }

            if (peak_meter_r_clip && 
                TIME_AFTER(current_tick, peak_meter_clip_timeout_r)){
                peak_meter_r_clip = false;
            }
        }

        /* check for new max values */
        if (left > peak_meter_max_l) {
            peak_meter_max_l = left - 1;
            peak_meter_timeout_l = 
                current_tick + max_time_out[peak_meter_hold];
        }

        if (right > peak_meter_max_r) {
            peak_meter_max_r = right - 1;
            peak_meter_timeout_r = 
                current_tick + max_time_out[peak_meter_hold];
        }
    }

    /* draw the peak meter */
    lcd_clearrect(x, y, width, height);

    /* draw left */
    lcd_fillrect (x, y, left, height / 2 - 2 );
    if (peak_meter_max_l > 0) {
        lcd_drawline(x + peak_meter_max_l, y, 
                     x + peak_meter_max_l, y + height / 2 - 2 );
    }
    if (peak_meter_l_clip) {
        lcd_fillrect(x + meterwidth, y, 3, height / 2 - 1);
    }

    /* draw right */
    lcd_fillrect(x, y + height / 2 + 1, right, height / 2 - 2);
    if (peak_meter_max_r > 0) {
        lcd_drawline( x + peak_meter_max_r, y + height / 2, 
                      x + peak_meter_max_r, y + height - 2);
    }
    if (peak_meter_r_clip) {
        lcd_fillrect(x + meterwidth, y + height / 2, 3, height / 2 - 1);
    }

    /* draw scale end */
    lcd_drawline(x + meterwidth, y,
                 x + meterwidth, y + height - 2);
    
    /* draw dots for scale marks */
    for (i = 0; i < db_scale_count; i++) {
        /* The x-coordinates of interesting scale mark points 
           have been calculated before */
        lcd_invertpixel(db_scale_lcd_coord[i], y + height / 2 - 1);
    }

#ifdef PM_DEBUG
    /* display a bar to show how many calls to peak_meter_peek 
       have ocurred since the last display */
    lcd_invertrect(x, y, tmp, 3);

    if (tmp < PEEKS_PER_DRAW_SIZE) {
        peeks_per_redraw[tmp]++;
    }

    tmp = current_tick - pm_tick;
    if (tmp < TICKS_PER_DRAW_SIZE ){
        ticks_per_redraw[tmp] ++;
    }

    /* display a bar to show how many ticks have passed since 
       the last redraw */
    lcd_invertrect(x, y + height / 2, current_tick - pm_tick, 2);
    pm_tick = current_tick;
#endif

    last_left = left;
    last_right = right;
}

#ifdef PM_DEBUG
static void peak_meter_clear_histogram(void) {
    int i = 0;
    for (i = 0; i < TICKS_PER_DRAW_SIZE; i++) {
        ticks_per_redraw[i] = (unsigned int)0;
    }

    for (i = 0; i < PEEKS_PER_DRAW_SIZE; i++) {
        peeks_per_redraw[i] = (unsigned int)0;
    }
}

bool peak_meter_histogram(void) {
    int i;
    int btn = BUTTON_NONE;
    while ((btn & BUTTON_OFF) != BUTTON_OFF )
    {
        unsigned int max = 0;
        int y = 0;
        int x = 0;
        lcd_clear_display();

        for (i = 0; i < PEEKS_PER_DRAW_SIZE; i++) {
            max = MAX(max, peeks_per_redraw[i]);
        }

        for (i = 0; i < PEEKS_PER_DRAW_SIZE; i++) {
            x = peeks_per_redraw[i] * (LCD_WIDTH - 1)/ max;
            lcd_drawline(0, y + i, x, y + i);
        }

        y = PEEKS_PER_DRAW_SIZE + 1;
        max = 0;

        for (i = 0; i < TICKS_PER_DRAW_SIZE; i++) {
            max = MAX(max, ticks_per_redraw[i]);
        }

        for (i = 0; i < TICKS_PER_DRAW_SIZE; i++) {
            x = ticks_per_redraw[i] * (LCD_WIDTH - 1)/ max;
            lcd_drawline(0, y + i, x, y + i);
        }
        lcd_update();
        
        btn = button_get(true);
        if (btn == BUTTON_PLAY) {
            peak_meter_clear_histogram();
        }
    }
    return false;
}
#endif