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Add RVA2 tag support to MPD 

This patch adds RVA2 (relative volume adjustment) tag
support to mpd, as a fallback if no replaygain tags are
found. The code is almost directly from madplay (GPL).

RVA2 tags are generated for example by the "normalize" utility.

Updated by: Avuton Olrich <avuton@gmail.com>
This commit is contained in:
Pauli Virtanen 2008-12-28 13:02:34 +01:00 committed by Max Kellermann
parent ed9668f638
commit 65b18644e1
1 changed files with 94 additions and 0 deletions
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94
src/decoder/mp3_plugin.c
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@ -202,6 +202,95 @@ mp3_fill_buffer(struct mp3_data *data)
return true;
}
#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);