Libav 0.7.1
libavformat/mp3enc.c
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00001 /*
00002  * MP3 muxer
00003  * Copyright (c) 2003 Fabrice Bellard
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include <strings.h>
00023 #include "avformat.h"
00024 #include "id3v1.h"
00025 #include "id3v2.h"
00026 #include "rawenc.h"
00027 #include "libavutil/avstring.h"
00028 #include "libavutil/intreadwrite.h"
00029 #include "libavutil/opt.h"
00030 #include "libavutil/dict.h"
00031 
00032 static int id3v1_set_string(AVFormatContext *s, const char *key,
00033                             uint8_t *buf, int buf_size)
00034 {
00035     AVDictionaryEntry *tag;
00036     if ((tag = av_dict_get(s->metadata, key, NULL, 0)))
00037         av_strlcpy(buf, tag->value, buf_size);
00038     return !!tag;
00039 }
00040 
00041 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
00042 {
00043     AVDictionaryEntry *tag;
00044     int i, count = 0;
00045 
00046     memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
00047     buf[0] = 'T';
00048     buf[1] = 'A';
00049     buf[2] = 'G';
00050     count += id3v1_set_string(s, "TIT2",    buf +  3, 30);       //title
00051     count += id3v1_set_string(s, "TPE1",    buf + 33, 30);       //author|artist
00052     count += id3v1_set_string(s, "TALB",    buf + 63, 30);       //album
00053     count += id3v1_set_string(s, "TDRL",    buf + 93,  4);       //date
00054     count += id3v1_set_string(s, "comment", buf + 97, 30);
00055     if ((tag = av_dict_get(s->metadata, "TRCK", NULL, 0))) { //track
00056         buf[125] = 0;
00057         buf[126] = atoi(tag->value);
00058         count++;
00059     }
00060     buf[127] = 0xFF; /* default to unknown genre */
00061     if ((tag = av_dict_get(s->metadata, "TCON", NULL, 0))) { //genre
00062         for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
00063             if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
00064                 buf[127] = i;
00065                 count++;
00066                 break;
00067             }
00068         }
00069     }
00070     return count;
00071 }
00072 
00073 /* simple formats */
00074 
00075 static void id3v2_put_size(AVFormatContext *s, int size)
00076 {
00077     avio_w8(s->pb, size >> 21 & 0x7f);
00078     avio_w8(s->pb, size >> 14 & 0x7f);
00079     avio_w8(s->pb, size >> 7  & 0x7f);
00080     avio_w8(s->pb, size       & 0x7f);
00081 }
00082 
00083 static int string_is_ascii(const uint8_t *str)
00084 {
00085     while (*str && *str < 128) str++;
00086     return !*str;
00087 }
00088 
00094 static int id3v2_put_ttag(AVFormatContext *s, const char *str1, const char *str2,
00095                           uint32_t tag, enum ID3v2Encoding enc)
00096 {
00097     int len;
00098     uint8_t *pb;
00099     int (*put)(AVIOContext*, const char*);
00100     AVIOContext *dyn_buf;
00101     if (avio_open_dyn_buf(&dyn_buf) < 0)
00102         return AVERROR(ENOMEM);
00103 
00104     /* check if the strings are ASCII-only and use UTF16 only if
00105      * they're not */
00106     if (enc == ID3v2_ENCODING_UTF16BOM && string_is_ascii(str1) &&
00107         (!str2 || string_is_ascii(str2)))
00108         enc = ID3v2_ENCODING_ISO8859;
00109 
00110     avio_w8(dyn_buf, enc);
00111     if (enc == ID3v2_ENCODING_UTF16BOM) {
00112         avio_wl16(dyn_buf, 0xFEFF);      /* BOM */
00113         put = avio_put_str16le;
00114     } else
00115         put = avio_put_str;
00116 
00117     put(dyn_buf, str1);
00118     if (str2)
00119         put(dyn_buf, str2);
00120     len = avio_close_dyn_buf(dyn_buf, &pb);
00121 
00122     avio_wb32(s->pb, tag);
00123     id3v2_put_size(s, len);
00124     avio_wb16(s->pb, 0);
00125     avio_write(s->pb, pb, len);
00126 
00127     av_freep(&pb);
00128     return len + ID3v2_HEADER_SIZE;
00129 }
00130 
00131 static int mp3_write_trailer(struct AVFormatContext *s)
00132 {
00133     uint8_t buf[ID3v1_TAG_SIZE];
00134 
00135     /* write the id3v1 tag */
00136     if (id3v1_create_tag(s, buf) > 0) {
00137         avio_write(s->pb, buf, ID3v1_TAG_SIZE);
00138         avio_flush(s->pb);
00139     }
00140     return 0;
00141 }
00142 
00143 #if CONFIG_MP2_MUXER
00144 AVOutputFormat ff_mp2_muxer = {
00145     "mp2",
00146     NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
00147     "audio/x-mpeg",
00148     "mp2,m2a",
00149     0,
00150     CODEC_ID_MP2,
00151     CODEC_ID_NONE,
00152     NULL,
00153     ff_raw_write_packet,
00154     mp3_write_trailer,
00155 };
00156 #endif
00157 
00158 #if CONFIG_MP3_MUXER
00159 typedef struct MP3Context {
00160     const AVClass *class;
00161     int id3v2_version;
00162 } MP3Context;
00163 
00164 static const AVOption options[] = {
00165     { "id3v2_version", "Select ID3v2 version to write. Currently 3 and 4 are supported.",
00166       offsetof(MP3Context, id3v2_version), FF_OPT_TYPE_INT, {.dbl = 4}, 3, 4, AV_OPT_FLAG_ENCODING_PARAM},
00167     { NULL },
00168 };
00169 
00170 static const AVClass mp3_muxer_class = {
00171     .class_name     = "MP3 muxer",
00172     .item_name      = av_default_item_name,
00173     .option         = options,
00174     .version        = LIBAVUTIL_VERSION_INT,
00175 };
00176 
00177 static int id3v2_check_write_tag(AVFormatContext *s, AVDictionaryEntry *t, const char table[][4],
00178                                  enum ID3v2Encoding enc)
00179 {
00180     uint32_t tag;
00181     int i;
00182 
00183     if (t->key[0] != 'T' || strlen(t->key) != 4)
00184         return -1;
00185     tag = AV_RB32(t->key);
00186     for (i = 0; *table[i]; i++)
00187         if (tag == AV_RB32(table[i]))
00188             return id3v2_put_ttag(s, t->value, NULL, tag, enc);
00189     return -1;
00190 }
00191 
00196 static int mp3_write_header(struct AVFormatContext *s)
00197 {
00198     MP3Context  *mp3 = s->priv_data;
00199     AVDictionaryEntry *t = NULL;
00200     int totlen = 0, enc = mp3->id3v2_version == 3 ? ID3v2_ENCODING_UTF16BOM :
00201                                                     ID3v2_ENCODING_UTF8;
00202     int64_t size_pos, cur_pos;
00203 
00204     avio_wb32(s->pb, MKBETAG('I', 'D', '3', mp3->id3v2_version));
00205     avio_w8(s->pb, 0);
00206     avio_w8(s->pb, 0); /* flags */
00207 
00208     /* reserve space for size */
00209     size_pos = avio_tell(s->pb);
00210     avio_wb32(s->pb, 0);
00211 
00212     ff_metadata_conv(&s->metadata, ff_id3v2_34_metadata_conv, NULL);
00213     if (mp3->id3v2_version == 4)
00214         ff_metadata_conv(&s->metadata, ff_id3v2_4_metadata_conv, NULL);
00215 
00216     while ((t = av_dict_get(s->metadata, "", t, AV_DICT_IGNORE_SUFFIX))) {
00217         int ret;
00218 
00219         if ((ret = id3v2_check_write_tag(s, t, ff_id3v2_tags, enc)) > 0) {
00220             totlen += ret;
00221             continue;
00222         }
00223         if ((ret = id3v2_check_write_tag(s, t, mp3->id3v2_version == 3 ?
00224                                                ff_id3v2_3_tags : ff_id3v2_4_tags, enc)) > 0) {
00225             totlen += ret;
00226             continue;
00227         }
00228 
00229         /* unknown tag, write as TXXX frame */
00230         if ((ret = id3v2_put_ttag(s, t->key, t->value, MKBETAG('T', 'X', 'X', 'X'), enc)) < 0)
00231             return ret;
00232         totlen += ret;
00233     }
00234 
00235     cur_pos = avio_tell(s->pb);
00236     avio_seek(s->pb, size_pos, SEEK_SET);
00237     id3v2_put_size(s, totlen);
00238     avio_seek(s->pb, cur_pos, SEEK_SET);
00239 
00240     return 0;
00241 }
00242 
00243 AVOutputFormat ff_mp3_muxer = {
00244     "mp3",
00245     NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
00246     "audio/x-mpeg",
00247     "mp3",
00248     sizeof(MP3Context),
00249     CODEC_ID_MP3,
00250     CODEC_ID_NONE,
00251     mp3_write_header,
00252     ff_raw_write_packet,
00253     mp3_write_trailer,
00254     AVFMT_NOTIMESTAMPS,
00255     .priv_class = &mp3_muxer_class,
00256 };
00257 #endif