Add replaygain side data type and code for parsing replaygain tags.

2 files changed, 185 insertions, 0 deletions

diff --git a/libavformat/replaygain.c b/libavformat/replaygain.c
new file mode 100644
index 0000000000..cf4dbf8f01
--- /dev/null
+++ b/libavformat/replaygain.c
@@ -0,0 +1,154 @@
+/*
+ * 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
+ */
+
+/**
+ * @file
+ * replaygain tags parsing
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "libavutil/avstring.h"
+#include "libavutil/dict.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/mathematics.h"
+#include "libavutil/mem.h"
+#include "libavutil/replaygain.h"
+
+#include "avformat.h"
+#include "replaygain.h"
+
+static int32_t parse_gain(const char *gain)
+{
+    char *fraction;
+    int  scale = 10000;
+    int32_t mb = 0;
+    int db;
+
+    if (!gain)
+        return INT32_MIN;
+
+    gain += strspn(gain, " \t");
+
+    db = strtol(gain, &fraction, 0);
+    if (*fraction++ == '.') {
+        while (av_isdigit(*fraction) && scale) {
+            mb += scale * (*fraction - '0');
+            scale /= 10;
+            fraction++;
+        }
+    }
+
+    if (abs(db) > (INT32_MAX - mb) / 100000)
+        return INT32_MIN;
+
+    return db * 100000 + FFSIGN(db) * mb;
+}
+
+static uint32_t parse_peak(const uint8_t *peak)
+{
+    int64_t val = 0;
+    int64_t scale = 1;
+
+    if (!peak)
+        return 0;
+
+    peak += strspn(peak, " \t");
+
+    if (peak[0] == '1' && peak[1] == '.')
+        return UINT32_MAX;
+    else if (!(peak[0] == '0' && peak[1] == '.'))
+        return 0;
+
+    peak += 2;
+
+    while (av_isdigit(*peak)) {
+        int digit = *peak - '0';
+
+        if (scale > INT64_MAX / 10)
+            break;
+
+        val    = 10 * val + digit;
+        scale *= 10;
+
+        peak++;
+    }
+
+    return av_rescale(val, UINT32_MAX, scale);
+}
+
+static int replaygain_export(AVStream *st,
+                             const uint8_t *track_gain, const uint8_t *track_peak,
+                             const uint8_t *album_gain, const uint8_t *album_peak)
+{
+    AVPacketSideData *sd, *tmp;
+    AVReplayGain *replaygain;
+    uint8_t *data;
+    int32_t tg, ag;
+    uint32_t tp, ap;
+
+    tg = parse_gain(track_gain);
+    ag = parse_gain(album_gain);
+    tp = parse_peak(track_peak);
+    ap = parse_peak(album_peak);
+
+    if (tg == INT32_MIN && ag == INT32_MIN)
+        return 0;
+
+    replaygain = av_mallocz(sizeof(*replaygain));
+    if (!replaygain)
+        return AVERROR(ENOMEM);
+
+    tmp = av_realloc_array(st->side_data, st->nb_side_data + 1, sizeof(*tmp));
+    if (!tmp) {
+        av_freep(&replaygain);
+        return AVERROR(ENOMEM);
+    }
+    st->side_data = tmp;
+    st->nb_side_data++;
+
+    sd = &st->side_data[st->nb_side_data - 1];
+    sd->type = AV_PKT_DATA_REPLAYGAIN;
+    sd->data = (uint8_t*)replaygain;
+    sd->size = sizeof(*replaygain);
+
+    replaygain->track_gain = tg;
+    replaygain->track_peak = tp;
+    replaygain->album_gain = ag;
+    replaygain->album_peak = ap;
+
+    return 0;
+}
+
+int ff_replaygain_export(AVStream *st, AVDictionary *metadata)
+{
+    const AVDictionaryEntry *tg, *tp, *ag, *ap;
+
+    tg = av_dict_get(metadata, "REPLAYGAIN_TRACK_GAIN", NULL, 0);
+    tp = av_dict_get(metadata, "REPLAYGAIN_TRACK_PEAK", NULL, 0);
+    ag = av_dict_get(metadata, "REPLAYGAIN_ALBUM_GAIN", NULL, 0);
+    ap = av_dict_get(metadata, "REPLAYGAIN_ALBUM_PEAK", NULL, 0);
+
+    return replaygain_export(st,
+                             tg ? tg->value : NULL,
+                             tp ? tp->value : NULL,
+                             ag ? ag->value : NULL,
+                             ap ? ap->value : NULL);
+}
diff --git a/libavformat/replaygain.h b/libavformat/replaygain.h
new file mode 100644
index 0000000000..641b7a299b
--- /dev/null
+++ b/libavformat/replaygain.h
@@ -0,0 +1,31 @@
+/*
+ * 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
+ */
+
+#ifndef AVFORMAT_REPLAYGAIN_H
+#define AVFORMAT_REPLAYGAIN_H
+
+#include "libavutil/dict.h"
+
+#include "avformat.h"
+
+/**
+ * Parse replaygain tags and export them as per-stream side data.
+ */
+int ff_replaygain_export(AVStream *st, AVDictionary *metadata);
+
+#endif /* AVFORMAT_REPLAYGAIN_H */