1 files changed, 214 insertions, 0 deletions

diff --git a/lib/rbcodec/dsp/crossfeed.c b/lib/rbcodec/dsp/crossfeed.c
new file mode 100644
index 0000000000..ecb55644ee
--- /dev/null
+++ b/lib/rbcodec/dsp/crossfeed.c
@@ -0,0 +1,214 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2006 Thom Johansen
+ * Copyright (C) 2012 Michael Sevakis
+ *
+ * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#include "config.h"
+#include "system.h"
+#include "dsp.h"
+#include "dsp_filter.h"
+#include "fixedpoint.h"
+#include "fracmul.h"
+#include "replaygain.h"
+#include <string.h>
+#include "dsp_proc_entry.h"
+
+/* Implemented here or in target assembly code */
+void crossfeed_process(struct dsp_proc_entry *this, struct dsp_buffer **buf_p);
+
+/**
+ * Applies crossfeed to the stereo signal.
+ *
+ * Crossfeed is a process where listening over speakers is simulated. This
+ * is good for old hard panned stereo records, which might be quite fatiguing
+ * to listen to on headphones with no crossfeed.
+ */
+
+/* Crossfeed */
+static struct crossfeed_state
+{
+    int32_t gain;           /* 00h: Direct path gain */
+    int32_t coefs[3];       /* 04h: Coefficients for the shelving filter */
+    int32_t history[4];     /* 10h: Format is x[n - 1], y[n - 1] (L + R) */
+    int32_t delay[13*2];    /* 20h: Delay line buffer (L + R interleaved) */
+    int32_t *index;         /* 88h: Current pointer into the delay line */
+    struct dsp_config *dsp; /* 8ch: Current DSP */
+                            /* 90h */
+} crossfeed_state IBSS_ATTR;
+
+/* Discard the sample histories */
+static void crossfeed_flush(struct dsp_proc_entry *this)
+{
+    struct crossfeed_state *state = (void *)this->data;
+    memset(state->history, 0, sizeof (state->history));
+    memset(state->delay, 0, sizeof (state->delay));
+    state->index = state->delay;
+}
+
+
+/** DSP interface **/
+
+/* Crossfeed boot/format change function */
+static void crossfeed_process_new_format(struct dsp_proc_entry *this,
+                                         struct dsp_buffer **buf_p)
+{
+    struct crossfeed_state *state = (void *)this->data;
+    struct dsp_buffer *buf = *buf_p;
+
+    DSP_PRINT_FORMAT(DSP_PROC_CROSSFEED, DSP_PROC_CROSSFEED, buf->format);
+
+    bool active = buf->format.num_channels >= 2;
+    dsp_proc_activate(state->dsp, DSP_PROC_CROSSFEED, active);
+
+    if (!active)
+    {
+        /* Can't do this. Sleep until next change */
+        crossfeed_flush(this);
+        DEBUGF("  DSP_PROC_CROSSFEED- deactivated\n");
+        return;
+    }
+
+    /* Switch to the real function and call it once */
+    this->process[0] = crossfeed_process;
+    dsp_proc_call(this, buf_p, (unsigned)buf->format.changed - 1);
+}
+
+/* Enable or disable the crossfeed */
+void dsp_crossfeed_enable(bool enable)
+{
+    if (enable != !crossfeed_state.dsp)
+        return;
+
+    struct dsp_config *dsp = dsp_get_config(CODEC_IDX_AUDIO);
+    dsp_proc_enable(dsp, DSP_PROC_CROSSFEED, enable);
+}
+
+/* Set the gain of the dry mix */
+void dsp_set_crossfeed_direct_gain(int gain)
+{
+    uint32_t gain32 = get_replaygain_int(gain * 10);
+    crossfeed_state.gain =
+        gain32 >= (0x80000000ul >> 7) ? 0x7ffffffful: (gain32 << 7);
+}
+
+/* Both gains should be below 0 dB */
+void dsp_set_crossfeed_cross_params(long lf_gain, long hf_gain, long cutoff)
+{
+    int32_t *c = crossfeed_state.coefs;
+    long scaler = get_replaygain_int(lf_gain * 10) << 7;
+
+    cutoff = 0xffffffff / NATIVE_FREQUENCY * cutoff;
+    hf_gain -= lf_gain;
+    /* Divide cutoff by sqrt(10^(hf_gain/20)) to place cutoff at the -3 dB
+     * point instead of shelf midpoint. This is for compatibility with the old
+     * crossfeed shelf filter and should be removed if crossfeed settings are
+     * ever made incompatible for any other good reason.
+     */
+    cutoff = fp_div(cutoff, get_replaygain_int(hf_gain*5), 24);
+    filter_shelf_coefs(cutoff, hf_gain, false, c);
+    /* Scale coefs by LF gain and shift them to s0.31 format. We have no gains
+     * over 1 and can do this safely
+     */
+    c[0] = FRACMUL_SHL(c[0], scaler, 4);
+    c[1] = FRACMUL_SHL(c[1], scaler, 4);
+    c[2] <<= 4;
+}
+
+#if !defined(CPU_COLDFIRE) && !defined(CPU_ARM)
+/* Apply the crossfade to the buffer in place */
+void crossfeed_process(struct dsp_proc_entry *this, struct dsp_buffer **buf_p)
+{
+    struct crossfeed_state *state = (void *)this->data;
+    struct dsp_buffer *buf = *buf_p;
+   
+    int32_t *hist_l = &state->history[0];
+    int32_t *hist_r = &state->history[2];
+    int32_t *delay = state->delay;
+    int32_t *coefs = &state->coefs[0];
+    int32_t gain = state->gain;
+    int32_t *di = state->index;
+
+    int count = buf->remcount;
+
+    for (int i = 0; i < count; i++)
+    {
+        int32_t left = buf->p32[0][i];
+        int32_t right = buf->p32[1][i];
+
+        /* Filter delayed sample from left speaker */
+        int32_t acc = FRACMUL(*di, coefs[0]);
+        acc += FRACMUL(hist_l[0], coefs[1]);
+        acc += FRACMUL(hist_l[1], coefs[2]);
+        /* Save filter history for left speaker */
+        hist_l[1] = acc;
+        hist_l[0] = *di;
+        *di++ = left;
+        /* Filter delayed sample from right speaker */
+        acc = FRACMUL(*di, coefs[0]);
+        acc += FRACMUL(hist_r[0], coefs[1]);
+        acc += FRACMUL(hist_r[1], coefs[2]);
+        /* Save filter history for right speaker */
+        hist_r[1] = acc;
+        hist_r[0] = *di;
+        *di++ = right;
+        /* Now add the attenuated direct sound and write to outputs */
+        buf->p32[0][i] = FRACMUL(left, gain) + hist_r[1];
+        buf->p32[1][i] = FRACMUL(right, gain) + hist_l[1];
+
+        /* Wrap delay line index if bigger than delay line size */
+        if (di >= delay + 13*2)
+            di = delay;
+    }
+
+    /* Write back local copies of data we've modified */
+    state->index = di;
+}
+#endif /* CPU */
+
+/* DSP message hook */
+static intptr_t crossfeed_configure(struct dsp_proc_entry *this,
+                                    struct dsp_config *dsp,
+                                    unsigned int setting,
+                                    intptr_t value)
+{
+    switch (setting)
+    {
+    case DSP_PROC_INIT:
+        this->data = (intptr_t)&crossfeed_state;
+        this->process[0] = crossfeed_process_new_format;
+        this->process[1] = crossfeed_process_new_format;
+        ((struct crossfeed_state *)this->data)->dsp = dsp;
+        dsp_proc_activate(dsp, DSP_PROC_CROSSFEED, true);
+    case DSP_FLUSH:
+        crossfeed_flush(this);
+        break;
+
+    case DSP_PROC_CLOSE:
+        ((struct crossfeed_state *)this->data)->dsp = NULL;
+        break;
+    }
+
+    return 1;
+    (void)value;
+}
+
+/* Database entry */
+DSP_PROC_DB_ENTRY(
+    CROSSFEED,
+    crossfeed_configure);