From fe4b16ed96d24f5a33832fe906c1a7d2c0e59182 Mon Sep 17 00:00:00 2001 From: "J. Alexander Treuman" Date: Wed, 22 Aug 2007 16:42:08 +0000 Subject: inputPlugins/mp3_plugin: parse LAME tags for ReplayGain info Parse ReplayGain info in LAME tags and use it if no ID3v2 ReplayGain tags are found. This is currently a bit unsafe, as apparently some LAME tags have bogus ReplayGain values. But I'm finding a lot of MP3s with valid LAME tags that fail the LAME tag CRC check. So until I figure out why that's happening, it's an unreliable method for checking if the LAME tag is valid. A big thanks to tmz for writing the original patch. git-svn-id: https://svn.musicpd.org/mpd/trunk@6798 09075e82-0dd4-0310-85a5-a0d7c8717e4f --- src/inputPlugins/mp3_plugin.c | 150 +++++++++++++++++++++++++++++------------- 1 file changed, 104 insertions(+), 46 deletions(-) diff --git a/src/inputPlugins/mp3_plugin.c b/src/inputPlugins/mp3_plugin.c index 3c958705a..43783070d 100644 --- a/src/inputPlugins/mp3_plugin.c +++ b/src/inputPlugins/mp3_plugin.c @@ -41,17 +41,17 @@ #include #include -#define FRAMES_CUSHION 2000 +#define FRAMES_CUSHION 2000 -#define READ_BUFFER_SIZE 40960 +#define READ_BUFFER_SIZE 40960 -#define DECODE_SKIP -3 -#define DECODE_BREAK -2 -#define DECODE_CONT -1 -#define DECODE_OK 0 +#define DECODE_SKIP -3 +#define DECODE_BREAK -2 +#define DECODE_CONT -1 +#define DECODE_OK 0 -#define MUTEFRAME_SKIP 1 -#define MUTEFRAME_SEEK 2 +#define MUTEFRAME_SKIP 1 +#define MUTEFRAME_SEEK 2 /* the number of samples of silence the decoder inserts at start */ #define DECODERDELAY 529 @@ -498,16 +498,20 @@ enum { XING_SCALE = 0x00000008L }; +struct version { + int major; + int minor; +}; + struct lame { - char encoder[10]; /* 9 byte encoder name/version ("LAME3.97b") */ -#if 0 - /* See related comment in parse_lame() */ - float peak; /* replaygain peak */ - float trackGain; /* replaygain track gain */ - float albumGain; /* replaygain album gain */ -#endif - int encoderDelay; /* # of added samples at start of mp3 */ - int encoderPadding; /* # of added samples at end of mp3 */ + char encoder[10]; /* 9 byte encoder name/version ("LAME3.97b") */ + struct version version; /* struct containing just the version */ + float peak; /* replaygain peak */ + float trackGain; /* replaygain track gain */ + float albumGain; /* replaygain album gain */ + int encoderDelay; /* # of added samples at start of mp3 */ + int encoderPadding; /* # of added samples at end of mp3 */ + int crc; /* CRC of the first 190 bytes of this frame */ }; static int parse_xing(struct xing *xing, struct mad_bitptr *ptr, int *oldbitlen) @@ -585,52 +589,94 @@ fail: static int parse_lame(struct lame *lame, struct mad_bitptr *ptr, int *bitlen) { + int adj = 0; + int name; + int orig; + int sign; + int gain; int i; /* Unlike the xing header, the lame tag has a fixed length. Fail if * not all 36 bytes (288 bits) are there. */ - if (*bitlen < 288) return 0; + if (*bitlen < 288) + return 0; - for (i = 0; i < 9; i++) lame->encoder[i] = (char)mad_bit_read(ptr, 8); + for (i = 0; i < 9; i++) + lame->encoder[i] = (char)mad_bit_read(ptr, 8); lame->encoder[9] = '\0'; + *bitlen -= 72; + /* This is technically incorrect, since the encoder might not be lame. * But there's no other way to determine if this is a lame tag, and we * wouldn't want to go reading a tag that's not there. */ - if (strncmp(lame->encoder, "LAME", 4) != 0) return 0; + if (strncmp(lame->encoder, "LAME", 4) != 0) + return 0; -#if 0 - /* Apparently lame versions <3.97b1 do not calculate replaygain. I'm - * using lame 3.97b2, and while it does calculate replaygain, it's - * setting the values to 0. Using --replaygain-(fast|accurate) doesn't - * make any difference. Leaving this code unused until we have a way - * of testing it. -- jat */ + if (sscanf(lame->encoder+4, "%u.%u", + &lame->version.major, &lame->version.minor) != 2) + return 0; - mad_bit_read(ptr, 16); + DEBUG("detected LAME version %i.%i (\"%s\")\n", + lame->version.major, lame->version.minor, lame->encoder); - mad_bit_read(ptr, 32); /* peak */ + /* The reference volume was changed from the 83dB used in the + * ReplayGain spec to 89dB in lame 3.95.1. Bump the gain for older + * versions, since everyone else uses 89dB instead of 83dB. + * Unfortunately, lame didn't differentiate between 3.95 and 3.95.1, so + * it's impossible to make the proper adjustment for 3.95. + * Fortunately, 3.95 was only out for about a day before 3.95.1 was + * released. -- tmz */ + if (lame->version.major < 3 || + (lame->version.major == 3 && lame->version.minor < 95)) + adj = 6; - mad_bit_read(ptr, 6); /* header */ - bits = mad_bit_read(ptr, 1); /* sign bit */ - lame->trackGain = mad_bit_read(ptr, 9); /* gain*10 */ - lame->trackGain = (bits ? -lame->trackGain : lame->trackGain) / 10; + mad_bit_read(ptr, 16); - mad_bit_read(ptr, 6); /* header */ - bits = mad_bit_read(ptr, 1); /* sign bit */ - lame->albumGain = mad_bit_read(ptr, 9); /* gain*10 */ - lame->albumGain = (bits ? -lame->albumGain : lame->albumGain) / 10; + lame->peak = mad_f_todouble(mad_bit_read(ptr, 32) << 5); /* peak */ + DEBUG("LAME peak found: %f\n", lame->peak); + + lame->trackGain = 0; + name = mad_bit_read(ptr, 3); /* gain name */ + orig = mad_bit_read(ptr, 3); /* gain originator */ + sign = mad_bit_read(ptr, 1); /* sign bit */ + gain = mad_bit_read(ptr, 9); /* gain*10 */ + if (gain && name == 1 && orig != 0) { + lame->trackGain = ((sign ? -gain : gain) / 10.0) + adj; + DEBUG("LAME track gain found: %f\n", lame->trackGain); + } - mad_bit_read(ptr, 16); + /* tmz reports that this isn't currently written by any version of lame + * (as of 3.97). Since we have no way of testing it, don't use it. + * Wouldn't want to go blowing someone's ears just because we read it + * wrong. :P -- jat */ + lame->albumGain = 0; +#if 0 + name = mad_bit_read(ptr, 3); /* gain name */ + orig = mad_bit_read(ptr, 3); /* gain originator */ + sign = mad_bit_read(ptr, 1); /* sign bit */ + gain = mad_bit_read(ptr, 9); /* gain*10 */ + if (gain && name == 2 && orig != 0) { + lame->albumGain = ((sign ? -gain : gain) / 10.0) + adj; + DEBUG("LAME album gain found: %f\n", lame->trackGain); + } #else - mad_bit_read(ptr, 96); + mad_bit_read(ptr, 16); #endif + mad_bit_read(ptr, 16); + lame->encoderDelay = mad_bit_read(ptr, 12); lame->encoderPadding = mad_bit_read(ptr, 12); - mad_bit_read(ptr, 96); + DEBUG("encoder delay is %i, encoder padding is %i\n", + lame->encoderDelay, lame->encoderPadding); - *bitlen -= 288; + mad_bit_read(ptr, 80); + + lame->crc = mad_bit_read(ptr, 16); + + *bitlen -= 216; return 1; } @@ -694,18 +740,30 @@ static int decodeFirstFrame(mp3DecodeData * data, DecoderControl * dc, data->foundXing = 1; data->muteFrame = MUTEFRAME_SKIP; - if (gaplessPlaybackEnabled && data->inStream->seekable && - parse_lame(&lame, &ptr, &bitlen)) { - data->dropSamplesAtStart = lame.encoderDelay + DECODERDELAY; - data->dropSamplesAtEnd = lame.encoderPadding; - } - if ((xing.flags & XING_FRAMES) && xing.frames) { mad_timer_t duration = data->frame.header.duration; mad_timer_multiply(&duration, xing.frames); data->totalTime = ((float)mad_timer_count(duration, MAD_UNITS_MILLISECONDS)) / 1000; data->maxFrames = xing.frames; } + + if (parse_lame(&lame, &ptr, &bitlen)) { + if (gaplessPlaybackEnabled && + data->inStream->seekable) { + data->dropSamplesAtStart = lame.encoderDelay + + DECODERDELAY; + data->dropSamplesAtEnd = lame.encoderPadding; + } + + /* Album gain isn't currently used. See comment in + * parse_lame() for details. -- jat */ + if (replayGainInfo && !*replayGainInfo && + lame.trackGain) { + *replayGainInfo = newReplayGainInfo(); + (*replayGainInfo)->trackGain = lame.trackGain; + (*replayGainInfo)->trackPeak = lame.peak; + } + } } if (!data->maxFrames) return -1; -- cgit v1.2.3