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-rw-r--r--src/decoder/mp3_plugin.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/src/decoder/mp3_plugin.c b/src/decoder/mp3_plugin.c
index 3a908299f..6fedf3766 100644
--- a/src/decoder/mp3_plugin.c
+++ b/src/decoder/mp3_plugin.c
@@ -203,6 +203,95 @@ mp3_fill_buffer(struct mp3_data *data)
}
#ifdef HAVE_ID3TAG
+/* Parse mp3 RVA2 frame. Shamelessly stolen from madplay. */
+static int parse_rva2(struct id3_tag * tag, struct replay_gain_info * replay_gain_info)
+{
+ struct id3_frame const * frame;
+
+ id3_latin1_t const *id;
+ id3_byte_t const *data;
+ id3_length_t length;
+ int found;
+
+ enum {
+ CHANNEL_OTHER = 0x00,
+ CHANNEL_MASTER_VOLUME = 0x01,
+ CHANNEL_FRONT_RIGHT = 0x02,
+ CHANNEL_FRONT_LEFT = 0x03,
+ CHANNEL_BACK_RIGHT = 0x04,
+ CHANNEL_BACK_LEFT = 0x05,
+ CHANNEL_FRONT_CENTRE = 0x06,
+ CHANNEL_BACK_CENTRE = 0x07,
+ CHANNEL_SUBWOOFER = 0x08
+ };
+
+ found = 0;
+
+ /* relative volume adjustment information */
+
+ frame = id3_tag_findframe(tag, "RVA2", 0);
+ if (!frame) return 0;
+
+ id = id3_field_getlatin1(id3_frame_field(frame, 0));
+ data = id3_field_getbinarydata(id3_frame_field(frame, 1),
+ &length);
+
+ if (!id || !data) return 0;
+
+ /*
+ * "The 'identification' string is used to identify the
+ * situation and/or device where this adjustment should apply.
+ * The following is then repeated for every channel
+ *
+ * Type of channel $xx
+ * Volume adjustment $xx xx
+ * Bits representing peak $xx
+ * Peak volume $xx (xx ...)"
+ */
+
+ while (length >= 4) {
+ unsigned int peak_bytes;
+
+ peak_bytes = (data[3] + 7) / 8;
+ if (4 + peak_bytes > length)
+ break;
+
+ if (data[0] == CHANNEL_MASTER_VOLUME) {
+ signed int voladj_fixed;
+ double voladj_float;
+
+ /*
+ * "The volume adjustment is encoded as a fixed
+ * point decibel value, 16 bit signed integer
+ * representing (adjustment*512), giving +/- 64
+ * dB with a precision of 0.001953125 dB."
+ */
+
+ voladj_fixed = (data[1] << 8) | (data[2] << 0);
+ voladj_fixed |= -(voladj_fixed & 0x8000);
+
+ voladj_float = (double) voladj_fixed / 512;
+
+ replay_gain_info->tuples[REPLAY_GAIN_TRACK].peak = voladj_float;
+ replay_gain_info->tuples[REPLAY_GAIN_ALBUM].peak = voladj_float;
+
+ g_debug("parseRVA2: Relative Volume "
+ "%+.1f dB adjustment (%s)\n",
+ voladj_float, id);
+
+ found = 1;
+ break;
+ }
+
+ data += 4 + peak_bytes;
+ length -= 4 + peak_bytes;
+ }
+
+ return found;
+}
+#endif
+
+#ifdef HAVE_ID3TAG
static struct replay_gain_info *
parse_id3_replay_gain_info(struct id3_tag *tag)
{
@@ -244,6 +333,11 @@ parse_id3_replay_gain_info(struct id3_tag *tag)
free(value);
}
+ if (!found) {
+ /* fall back on RVA2 if no replaygain tags found */
+ found = parse_rva2(tag, replay_gain_info);
+ }
+
if (found)
return replay_gain_info;
replay_gain_info_free(replay_gain_info);