lavr: resampling: add support for s32p, fltp, and dblp internal sample formats

Based partially on implementation by Michael Niedermayer <michaelni@gmx.at> in
libswresample in FFmpeg. See commits:
7f1ae79d
24ab1abf

libavresample/resample_template.c

+/*
+ * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#if defined(CONFIG_RESAMPLE_DBL)
+#define SET_TYPE(func)  func ## _dbl
+#define FELEM         double
+#define FELEM2        double
+#define FELEML        double
+#define OUT(d, v) d = v
+#define DBL_TO_FELEM(d, v) d = v
+#elif defined(CONFIG_RESAMPLE_FLT)
+#define SET_TYPE(func)  func ## _flt
+#define FELEM         float
+#define FELEM2        float
+#define FELEML        float
+#define OUT(d, v) d = v
+#define DBL_TO_FELEM(d, v) d = v
+#elif defined(CONFIG_RESAMPLE_S32)
+#define SET_TYPE(func)  func ## _s32
+#define FELEM         int32_t
+#define FELEM2        int64_t
+#define FELEML        int64_t
+#define OUT(d, v) d = av_clipl_int32((v + (1 << 29)) >> 30)
+#define DBL_TO_FELEM(d, v) d = av_clipl_int32(llrint(v * (1 << 30)));
+#else
+#define SET_TYPE(func)  func ## _s16
+#define FELEM         int16_t
+#define FELEM2        int32_t
+#define FELEML        int64_t
+#define OUT(d, v) d = av_clip_int16((v + (1 << 14)) >> 15)
+#define DBL_TO_FELEM(d, v) d = av_clip_int16(lrint(v * (1 << 15)))
+#endif
+
+static void SET_TYPE(resample_one)(ResampleContext *c, int no_filter,
+                                   void *dst0, int dst_index, const void *src0,
+                                   int src_size, int index, int frac)
+{
+    FELEM *dst = dst0;
+    const FELEM *src = src0;
+
+    if (no_filter) {
+        dst[dst_index] = src[index];
+    } else {
+        int i;
+        int sample_index = index >> c->phase_shift;
+        FELEM2 val = 0;
+        FELEM *filter = ((FELEM *)c->filter_bank) +
+                        c->filter_length * (index & c->phase_mask);
+
+        if (sample_index < 0) {
+            for (i = 0; i < c->filter_length; i++)
+                val += src[FFABS(sample_index + i) % src_size] *
+                       (FELEM2)filter[i];
+        } else if (c->linear) {
+            FELEM2 v2 = 0;
+            for (i = 0; i < c->filter_length; i++) {
+                val += src[abs(sample_index + i)] * (FELEM2)filter[i];
+                v2  += src[abs(sample_index + i)] * (FELEM2)filter[i + c->filter_length];
+            }
+            val += (v2 - val) * (FELEML)frac / c->src_incr;
+        } else {
+            for (i = 0; i < c->filter_length; i++)
+                val += src[sample_index + i] * (FELEM2)filter[i];
+        }
+
+        OUT(dst[dst_index], val);
+    }
+}
+
+static void SET_TYPE(set_filter)(void *filter0, double *tab, int phase,
+                                 int tap_count)
+{
+    int i;
+    FELEM *filter = ((FELEM *)filter0) + phase * tap_count;
+    for (i = 0; i < tap_count; i++) {
+        DBL_TO_FELEM(filter[i], tab[i]);
+    }
+}
+
+#undef SET_TYPE
+#undef FELEM
+#undef FELEM2
+#undef FELEML
+#undef OUT
+#undef DBL_TO_FELEM

libavresample/utils.c

@@ -64,10 +64,30 @@ int avresample_open(AVAudioResampleContext *avr)
         enum AVSampleFormat out_fmt = av_get_planar_sample_fmt(avr->out_sample_fmt);
         int max_bps = FFMAX(av_get_bytes_per_sample(in_fmt),
                             av_get_bytes_per_sample(out_fmt));
-        if (avr->resample_needed || max_bps <= 2) {
+        if (max_bps <= 2) {
             avr->internal_sample_fmt = AV_SAMPLE_FMT_S16P;
         } else if (avr->mixing_needed) {
             avr->internal_sample_fmt = AV_SAMPLE_FMT_FLTP;
+        } else {
+            if (max_bps <= 4) {
+                if (in_fmt  == AV_SAMPLE_FMT_S32P ||
+                    out_fmt == AV_SAMPLE_FMT_S32P) {
+                    if (in_fmt  == AV_SAMPLE_FMT_FLTP ||
+                        out_fmt == AV_SAMPLE_FMT_FLTP) {
+                        /* if one is s32 and the other is flt, use dbl */
+                        avr->internal_sample_fmt = AV_SAMPLE_FMT_DBLP;
+                    } else {
+                        /* if one is s32 and the other is s32, s16, or u8, use s32 */
+                        avr->internal_sample_fmt = AV_SAMPLE_FMT_S32P;
+                    }
+                } else {
+                    /* if one is flt and the other is flt, s16 or u8, use flt */
+                    avr->internal_sample_fmt = AV_SAMPLE_FMT_FLTP;
+                }
+            } else {
+                /* if either is dbl, use dbl */
+                avr->internal_sample_fmt = AV_SAMPLE_FMT_DBLP;
+            }
         }
         av_log(avr, AV_LOG_DEBUG, "Using %s as internal sample format\n",
                av_get_sample_fmt_name(avr->internal_sample_fmt));