From 37ed4616f98abaec9da3fd8d47b6b00f45f29b37 Mon Sep 17 00:00:00 2001
From: Andre Noll <maan@systemlinux.org>
Date: Sat, 29 Nov 2008 21:26:53 +0100
Subject: [PATCH] Implement aac meta info support.

---
 NEWS      |   1 +
 aac_afh.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 135 insertions(+), 4 deletions(-)

diff --git a/NEWS b/NEWS
index 8487a6ad..4ed40f7c 100644
--- a/NEWS
+++ b/NEWS
@@ -12,6 +12,7 @@ amplification filter.
 	- overhaul of the virtual streaming system.
 	- mp3: id3 version 2 support via libid3tag (optional)
 	- ogg: vorbis comment support.
+	- aac meta info support.
 	- mp3 audio format handler cleanups.
 	- new filter: "amp" to amplify the amplitude of the audio stream
 	- new status item/database entry: amplification. It is
diff --git a/aac_afh.c b/aac_afh.c
index a4166d1a..80b50a4d 100644
--- a/aac_afh.c
+++ b/aac_afh.c
@@ -42,6 +42,135 @@ static int aac_find_stsz(unsigned char *buf, size_t buflen, off_t *skip)
 	return -E_STSZ;
 }
 
+static int atom_cmp(unsigned char *buf1, char *buf2)
+{
+	unsigned char *b2 = (unsigned char *)buf2;
+
+	if (buf1[0] != b2[0])
+		return 1;
+	if (buf1[1] != b2[1])
+		return 1;
+	if (buf1[2] != b2[2])
+		return 1;
+	if (buf1[3] != b2[3])
+		return 1;
+	return 0;
+}
+
+static int read_atom_header(unsigned char *buf, uint64_t *subsize, unsigned char type[5])
+{
+	int i;
+	uint64_t size = (buf[0] << 24) + (buf[1] << 16) + (buf[2] << 8) + buf[3];
+
+	memcpy(type, buf + 4, 4);
+	type[4] = '\0';
+
+	PARA_DEBUG_LOG("size: %llu, type: %s\n", (long long unsigned)size, type);
+	if (size != 1) {
+		*subsize = size;
+		return 8;
+	}
+	buf += 4;
+	size = 0;
+	for (i = 0; i < 8; i++)
+		size |= ((uint64_t)buf[i]) << ((7 - i) * 8);
+	*subsize = size;
+	return 16;
+}
+
+static char *get_tag(unsigned char *p, int size)
+{
+	char *buf;
+
+	assert(size > 0);
+	buf = para_malloc(size + 1);
+
+	memcpy(buf, p, size);
+	buf[size] = '\0';
+	PARA_DEBUG_LOG("size: %d: %s\n", size, buf);
+	return buf;
+}
+
+static char *read_tags(unsigned char *buf, size_t buflen)
+{
+	unsigned char *p = buf;
+	char *title = NULL, *artist = NULL, *album = NULL, *year = NULL,
+		*comment = NULL, *result;
+
+	while (p + 32 < buf + buflen) {
+		unsigned char *q, type1[5], type2[5];
+		uint64_t size1, size2;
+		int ret, ret2;
+
+		ret = read_atom_header(p, &size1, type1);
+		ret2 = read_atom_header(p + ret, &size2, type2);
+
+		if (size2 <= 16 || atom_cmp(type2, "data")) {
+			p += size1;
+			continue;
+		}
+		size2 -= 16;
+		q = p + ret + ret2 + 8;
+		if (q + size2 > buf + buflen)
+			break;
+		if (!atom_cmp(type1, "©ART"))
+			artist = get_tag(q, size2);
+		else if (!atom_cmp(type1, "©alb"))
+			album = get_tag(q, size2);
+		else if (!atom_cmp(type1, "©nam"))
+			title = get_tag(q, size2);
+		else if (!atom_cmp(type1, "©cmt"))
+			comment = get_tag(q, size2);
+		else if (!atom_cmp(type1, "©day"))
+			year = get_tag(q, size2);
+		p += size1;
+	}
+	result = make_taginfo(title, artist, album, year, comment);
+	free(title);
+	free(artist);
+	free(album);
+	free(year);
+	free(comment);
+	return result;
+}
+
+static char *read_meta(unsigned char *buf, size_t buflen)
+{
+	unsigned char *p = buf;
+
+	while (p + 4 < buf + buflen) {
+
+		if (p[0] != 'i' || p[1] != 'l' || p[2] != 's' || p[3] != 't') {
+			p++;
+			continue;
+		}
+		p += 4;
+		return read_tags(p, buflen - (p - buf));
+	}
+	return make_taginfo(NULL, NULL, NULL, NULL, NULL);
+}
+
+static char *aac_get_taginfo(unsigned char *buf, size_t buflen)
+{
+	int i;
+	uint64_t subsize;
+	unsigned char type[5];
+
+	for (i = 0; i + 24 < buflen; i++) {
+		unsigned char *p = buf + i;
+		if (p[0] != 'm' || p[1] != 'e' || p[2] != 't' || p[3] != 'a')
+			continue;
+		PARA_INFO_LOG("found metadata at offset %d\n", i);
+		i += 8;
+		p = buf + i;
+		i += read_atom_header(p, &subsize, type);
+		p = buf + i;
+		return read_meta(p, buflen - i);
+	}
+	PARA_INFO_LOG("no meta data\n");
+	return make_taginfo(NULL, NULL, NULL, NULL, NULL);
+}
+
 static ssize_t aac_compute_chunk_table(struct afh_info *afhi,
 		unsigned char *map, size_t numbytes)
 {
@@ -103,10 +232,12 @@ static int aac_get_file_info(char *map, size_t numbytes, __a_unused int fd,
 	mp4AudioSpecificConfig mp4ASC;
 	NeAACDecHandle handle = NULL;
 	unsigned char *umap = (unsigned char *) map;
+	char *taginfo;
 
 	ret = aac_find_esds(umap, numbytes, &skip, &decoder_len);
 	if (ret < 0)
 		goto out;
+	taginfo = aac_get_taginfo(umap, numbytes);
 	handle = aac_open();
 	ret = -E_AAC_AFH_INIT;
 	if (NeAACDecInit(handle, umap + skip, decoder_len, &rate, &channels))
@@ -137,11 +268,10 @@ static int aac_get_file_info(char *map, size_t numbytes, __a_unused int fd,
 	ret = (afhi->chunk_table[afhi->chunks_total] - afhi->chunk_table[0]) * 8; /* bits */
 	ret += (channels * afhi->seconds_total * 500); /* avoid rounding error */
 	afhi->bitrate = ret / (channels * afhi->seconds_total * 1000);
-	afhi->info_string = make_message("%s:\n%s:\n%s:\n",
+	afhi->info_string = make_message("%s:\n%s",
 		status_item_list[SI_AUDIO_FILE_INFO],
-		status_item_list[SI_TAGINFO1],
-		status_item_list[SI_TAGINFO2]
-	);
+		taginfo);
+	free(taginfo);
 	tv_scale(20, &afhi->chunk_tv, &afhi->eof_tv);
 	ret = 1;
 out:
-- 
2.39.5