/*
  * MP3 muxer
  * Copyright (c) 2003 Fabrice Bellard
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "avformat.h"

 #include "avio_internal.h"

 #include "id3v1.h"
 #include "id3v2.h"

 #include "rawenc.h"

 #include "libavutil/avstring.h"

 #include "libavcodec/mpegaudio.h"
 #include "libavcodec/mpegaudiodata.h"
 #include "libavcodec/mpegaudiodecheader.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/opt.h"

 #include "libavutil/dict.h"

 #include "libavutil/avassert.h"

 
 static int id3v1_set_string(AVFormatContext *s, const char *key,
                             uint8_t *buf, int buf_size)
 {

     AVDictionaryEntry *tag;
     if ((tag = av_dict_get(s->metadata, key, NULL, 0)))

         av_strlcpy(buf, tag->value, buf_size);

     return !!tag;
 }
 
 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
 {

     AVDictionaryEntry *tag;

     int i, count = 0;
 
     memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
     buf[0] = 'T';
     buf[1] = 'A';
     buf[2] = 'G';

     /* we knowingly overspecify each tag length by one byte to compensate for the mandatory null byte added by av_strlcpy */
     count += id3v1_set_string(s, "TIT2",    buf +  3, 30 + 1);       //title
     count += id3v1_set_string(s, "TPE1",    buf + 33, 30 + 1);       //author|artist
     count += id3v1_set_string(s, "TALB",    buf + 63, 30 + 1);       //album
     count += id3v1_set_string(s, "TDRL",    buf + 93,  4 + 1);       //date
     count += id3v1_set_string(s, "comment", buf + 97, 30 + 1);

     if ((tag = av_dict_get(s->metadata, "TRCK", NULL, 0))) { //track

         buf[125] = 0;
         buf[126] = atoi(tag->value);
         count++;
     }
     buf[127] = 0xFF; /* default to unknown genre */

     if ((tag = av_dict_get(s->metadata, "TCON", NULL, 0))) { //genre

         for(i = 0; i <= ID3v1_GENRE_MAX; i++) {

             if (!av_strcasecmp(tag->value, ff_id3v1_genre_str[i])) {

                 buf[127] = i;
                 count++;
                 break;
             }
         }
     }
     return count;
 }
 

 #define XING_NUM_BAGS 400
 #define XING_TOC_SIZE 100
 // maximum size of the xing frame: offset/Xing/flags/frames/size/TOC
 #define XING_MAX_SIZE (32 + 4 + 4 + 4 + 4 + XING_TOC_SIZE)

 typedef struct MP3Context {
     const AVClass *class;

     ID3v2EncContext id3;

     int id3v2_version;

     int write_id3v1;

 
     /* xing header */
     int64_t xing_offset;

     int32_t frames;
     int32_t size;
     uint32_t want;
     uint32_t seen;
     uint32_t pos;

     uint64_t bag[XING_NUM_BAGS];

     int initial_bitrate;
     int has_variable_bitrate;

     /* index of the audio stream */
     int audio_stream_idx;
     /* number of attached pictures we still need to write */
     int pics_to_write;

     /* audio packets are queued here until we get all the attached pictures */
     AVPacketList *queue, *queue_end;

 } MP3Context;

 static const uint8_t xing_offtbl[2][2] = {{32, 17}, {17, 9}};

 
 /*
  * Write an empty XING header and initialize respective data.
  */
 static int mp3_write_xing(AVFormatContext *s)
 {
     MP3Context       *mp3 = s->priv_data;

     AVCodecContext *codec = s->streams[mp3->audio_stream_idx]->codec;

     int              bitrate_idx;

     int              best_bitrate_idx = -1;

     int              best_bitrate_error= INT_MAX;

     int              xing_offset;

     int32_t          header, mask;

     MPADecodeHeader  c;

     int              srate_idx, ver = 0, i, channels;

     int              needed;

     const char      *vendor = (codec->flags & CODEC_FLAG_BITEXACT) ? "Lavf" : LIBAVFORMAT_IDENT;

     if (!s->pb->seekable)

         return 0;

     for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++) {
         const uint16_t base_freq = avpriv_mpa_freq_tab[i];

         if      (codec->sample_rate == base_freq)     ver = 0x3; // MPEG 1
         else if (codec->sample_rate == base_freq / 2) ver = 0x2; // MPEG 2
         else if (codec->sample_rate == base_freq / 4) ver = 0x0; // MPEG 2.5
         else continue;

         srate_idx = i;
         break;
     }

     if (i == FF_ARRAY_ELEMS(avpriv_mpa_freq_tab)) {

         av_log(s, AV_LOG_WARNING, "Unsupported sample rate, not writing Xing header.\n");

         return -1;
     }
 
     switch (codec->channels) {
     case 1:  channels = MPA_MONO;                                          break;
     case 2:  channels = MPA_STEREO;                                        break;

     default: av_log(s, AV_LOG_WARNING, "Unsupported number of channels, "
                     "not writing Xing header.\n");

              return -1;

     }
 
     /* dummy MPEG audio header */

     header  =  0xffU                                 << 24; // sync

     header |= (0x7 << 5 | ver << 3 | 0x1 << 1 | 0x1) << 16; // sync/audio-version/layer 3/no crc*/

     header |= (srate_idx << 2) <<  8;
     header |= channels << 6;
 

     for (bitrate_idx=1; bitrate_idx<15; bitrate_idx++) {
         int error;
         avpriv_mpegaudio_decode_header(&c, header | (bitrate_idx << (4+8)));
         error= FFABS(c.bit_rate - codec->bit_rate);
         if(error < best_bitrate_error){
             best_bitrate_error= error;
             best_bitrate_idx  = bitrate_idx;
         }
     }

     av_assert0(best_bitrate_idx >= 0);

 
     for (bitrate_idx= best_bitrate_idx;; bitrate_idx++) {

         if (15 == bitrate_idx)
             return -1;

         mask = bitrate_idx << (4+8);
         header |= mask;
         avpriv_mpegaudio_decode_header(&c, header);

         xing_offset=xing_offtbl[c.lsf == 1][c.nb_channels == 1];
         needed = 4              // header
                + xing_offset
                + 4              // xing tag
                + 4              // frames/size/toc flags
                + 4              // frames
                + 4              // size

                + XING_TOC_SIZE   // toc

                + 24
                ;

 
         if (needed <= c.frame_size)
             break;

         header &= ~mask;

     }
 
     avio_wb32(s->pb, header);

     ffio_fill(s->pb, 0, xing_offset);

     mp3->xing_offset = avio_tell(s->pb);

     ffio_wfourcc(s->pb, "Xing");

     avio_wb32(s->pb, 0x01 | 0x02 | 0x04);  // frames / size / TOC

     mp3->size = c.frame_size;
     mp3->want=1;
     mp3->seen=0;
     mp3->pos=0;

 
     avio_wb32(s->pb, 0);  // frames
     avio_wb32(s->pb, 0);  // size
 
     // toc

     for (i = 0; i < XING_TOC_SIZE; ++i)
         avio_w8(s->pb, (uint8_t)(255 * i / XING_TOC_SIZE));

     for (i = 0; i < strlen(vendor); ++i)
         avio_w8(s->pb, vendor[i]);
     for (; i < 21; ++i)
         avio_w8(s->pb, 0);
     avio_wb24(s->pb, FFMAX(codec->delay - 528 - 1, 0)<<12);
 

     ffio_fill(s->pb, 0, c.frame_size - needed);
 
     return 0;
 }
 
 /*
  * Add a frame to XING data.
  * Following lame's "VbrTag.c".
  */

 static void mp3_xing_add_frame(MP3Context *mp3, AVPacket *pkt)

 {
     int i;
 

     mp3->frames++;
     mp3->seen++;

     mp3->size += pkt->size;

     if (mp3->want == mp3->seen) {

         mp3->bag[mp3->pos] = mp3->size;

         if (XING_NUM_BAGS == ++mp3->pos) {

             /* shrink table to half size by throwing away each second bag. */

             for (i = 1; i < XING_NUM_BAGS; i += 2)

                 mp3->bag[i >> 1] = mp3->bag[i];

 
             /* double wanted amount per bag. */

             mp3->want *= 2;

             /* adjust current position to half of table size. */

             mp3->pos = XING_NUM_BAGS / 2;

         }
 

         mp3->seen = 0;

     }
 }
 

 static int mp3_write_audio_packet(AVFormatContext *s, AVPacket *pkt)

 {

     MP3Context  *mp3 = s->priv_data;
 

     if (pkt->data && pkt->size >= 4) {

         MPADecodeHeader c;

         int av_unused base;

         uint32_t head = AV_RB32(pkt->data);

         if (ff_mpa_check_header(head) < 0) {
             av_log(s, AV_LOG_WARNING, "Audio packet of size %d (starting with %08X...) "
                    "is invalid, writing it anyway.\n", pkt->size, head);
             return ff_raw_write_packet(s, pkt);
         }
         avpriv_mpegaudio_decode_header(&c, head);

         if (!mp3->initial_bitrate)
             mp3->initial_bitrate = c.bit_rate;

         if ((c.bit_rate == 0) || (mp3->initial_bitrate != c.bit_rate))
             mp3->has_variable_bitrate = 1;

 #ifdef FILTER_VBR_HEADERS

         /* filter out XING and INFO headers. */
         base = 4 + xing_offtbl[c.lsf == 1][c.nb_channels == 1];
 
         if (base + 4 <= pkt->size) {
             uint32_t v = AV_RB32(pkt->data + base);
 

             if (MKBETAG('X','i','n','g') == v || MKBETAG('I','n','f','o') == v)

                 return 0;
         }
 
         /* filter out VBRI headers. */
         base = 4 + 32;
 

         if (base + 4 <= pkt->size && MKBETAG('V','B','R','I') == AV_RB32(pkt->data + base))

             return 0;
 #endif
 

         if (mp3->xing_offset)
             mp3_xing_add_frame(mp3, pkt);

     }

 
     return ff_raw_write_packet(s, pkt);

 }
 

 static int mp3_queue_flush(AVFormatContext *s)
 {
     MP3Context *mp3 = s->priv_data;
     AVPacketList *pktl;
     int ret = 0, write = 1;
 
     ff_id3v2_finish(&mp3->id3, s->pb);
     mp3_write_xing(s);
 
     while ((pktl = mp3->queue)) {

         if (write && (ret = mp3_write_audio_packet(s, &pktl->pkt)) < 0)

             write = 0;
         av_free_packet(&pktl->pkt);
         mp3->queue = pktl->next;
         av_freep(&pktl);
     }
     mp3->queue_end = NULL;
     return ret;
 }
 

 static void mp3_update_xing(AVFormatContext *s)
 {
     MP3Context  *mp3 = s->priv_data;
     int i;
 
     /* replace "Xing" identification string with "Info" for CBR files. */
     if (!mp3->has_variable_bitrate) {
         avio_seek(s->pb, mp3->xing_offset, SEEK_SET);
         ffio_wfourcc(s->pb, "Info");
     }
 
     avio_seek(s->pb, mp3->xing_offset + 8, SEEK_SET);
     avio_wb32(s->pb, mp3->frames);
     avio_wb32(s->pb, mp3->size);
 
     avio_w8(s->pb, 0);  // first toc entry has to be zero.
 
     for (i = 1; i < XING_TOC_SIZE; ++i) {
         int j = i * mp3->pos / XING_TOC_SIZE;
         int seek_point = 256LL * mp3->bag[j] / mp3->size;
         avio_w8(s->pb, FFMIN(seek_point, 255));
     }
 
     avio_seek(s->pb, 0, SEEK_END);
 }
 

 static int mp3_write_trailer(struct AVFormatContext *s)

 {
     uint8_t buf[ID3v1_TAG_SIZE];

     MP3Context *mp3 = s->priv_data;

     if (mp3->pics_to_write) {

         av_log(s, AV_LOG_WARNING, "No packets were sent for some of the "
                "attached pictures.\n");
         mp3_queue_flush(s);
     }
 

     /* write the id3v1 tag */

     if (mp3->write_id3v1 && id3v1_create_tag(s, buf) > 0) {

         avio_write(s->pb, buf, ID3v1_TAG_SIZE);

     }

     if (mp3->xing_offset)
         mp3_update_xing(s);

     return 0;
 }
 

 static int query_codec(enum AVCodecID id, int std_compliance)

 {

     const CodecMime *cm= ff_id3v2_mime_tags;

     while(cm->id != AV_CODEC_ID_NONE) {

         if(id == cm->id)
             return MKTAG('A', 'P', 'I', 'C');
         cm++;
     }
     return -1;
 }
 

 #if CONFIG_MP2_MUXER

 AVOutputFormat ff_mp2_muxer = {

     .name              = "mp2",

     .long_name         = NULL_IF_CONFIG_SMALL("MP2 (MPEG audio layer 2)"),

     .mime_type         = "audio/x-mpeg",

     .extensions        = "mp2,m2a,mpa",

     .audio_codec       = AV_CODEC_ID_MP2,
     .video_codec       = AV_CODEC_ID_NONE,

     .write_packet      = ff_raw_write_packet,

     .flags             = AVFMT_NOTIMESTAMPS,

 };
 #endif
 
 #if CONFIG_MP3_MUXER

 
 static const AVOption options[] = {
     { "id3v2_version", "Select ID3v2 version to write. Currently 3 and 4 are supported.",

       offsetof(MP3Context, id3v2_version), AV_OPT_TYPE_INT, {.i64 = 4}, 3, 4, AV_OPT_FLAG_ENCODING_PARAM},

     { "write_id3v1", "Enable ID3v1 writing. ID3v1 tags are written in UTF-8 which may not be supported by most software.",

       offsetof(MP3Context, write_id3v1), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},

     { NULL },
 };
 
 static const AVClass mp3_muxer_class = {

     .class_name     = "MP3 muxer",
     .item_name      = av_default_item_name,
     .option         = options,
     .version        = LIBAVUTIL_VERSION_INT,

 };
 

 static int mp3_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     MP3Context *mp3 = s->priv_data;
 
     if (pkt->stream_index == mp3->audio_stream_idx) {
         if (mp3->pics_to_write) {
             /* buffer audio packets until we get all the pictures */
             AVPacketList *pktl = av_mallocz(sizeof(*pktl));
             if (!pktl)
                 return AVERROR(ENOMEM);
 
             pktl->pkt     = *pkt;

             pktl->pkt.buf = av_buffer_ref(pkt->buf);
             if (!pktl->pkt.buf) {
                 av_freep(&pktl);
                 return AVERROR(ENOMEM);
             }

 
             if (mp3->queue_end)
                 mp3->queue_end->next = pktl;
             else
                 mp3->queue = pktl;
             mp3->queue_end = pktl;
         } else

             return mp3_write_audio_packet(s, pkt);

     } else {
         int ret;
 
         /* warn only once for each stream */
         if (s->streams[pkt->stream_index]->nb_frames == 1) {
             av_log(s, AV_LOG_WARNING, "Got more than one picture in stream %d,"
                    " ignoring.\n", pkt->stream_index);
         }
         if (!mp3->pics_to_write || s->streams[pkt->stream_index]->nb_frames >= 1)
             return 0;
 
         if ((ret = ff_id3v2_write_apic(s, &mp3->id3, pkt)) < 0)
             return ret;
         mp3->pics_to_write--;
 
         /* flush the buffered audio packets */
         if (!mp3->pics_to_write &&
             (ret = mp3_queue_flush(s)) < 0)
             return ret;
     }
 
     return 0;
 }

 /**

  * Write an ID3v2 header at beginning of stream

  */
 
 static int mp3_write_header(struct AVFormatContext *s)
 {

     MP3Context  *mp3 = s->priv_data;

     int ret, i;

     /* check the streams -- we want exactly one audio and arbitrary number of
      * video (attached pictures) */
     mp3->audio_stream_idx = -1;
     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st = s->streams[i];
         if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {

             if (mp3->audio_stream_idx >= 0 || st->codec->codec_id != AV_CODEC_ID_MP3) {

                 av_log(s, AV_LOG_ERROR, "Invalid audio stream. Exactly one MP3 "
                        "audio stream is required.\n");
                 return AVERROR(EINVAL);
             }
             mp3->audio_stream_idx = i;
         } else if (st->codec->codec_type != AVMEDIA_TYPE_VIDEO) {
             av_log(s, AV_LOG_ERROR, "Only audio streams and pictures are allowed in MP3.\n");
             return AVERROR(EINVAL);
         }
     }
     if (mp3->audio_stream_idx < 0) {
         av_log(s, AV_LOG_ERROR, "No audio stream present.\n");
         return AVERROR(EINVAL);
     }
     mp3->pics_to_write = s->nb_streams - 1;
 
     ff_id3v2_start(&mp3->id3, s->pb, mp3->id3v2_version, ID3v2_DEFAULT_MAGIC);
     ret = ff_id3v2_write_metadata(s, &mp3->id3);

     if (ret < 0)
         return ret;

     if (!mp3->pics_to_write) {
         ff_id3v2_finish(&mp3->id3, s->pb);

         mp3_write_xing(s);

     }

     return 0;
 }
 

 AVOutputFormat ff_mp3_muxer = {

     .name              = "mp3",

     .long_name         = NULL_IF_CONFIG_SMALL("MP3 (MPEG audio layer 3)"),

     .mime_type         = "audio/x-mpeg",
     .extensions        = "mp3",
     .priv_data_size    = sizeof(MP3Context),

     .audio_codec       = AV_CODEC_ID_MP3,
     .video_codec       = AV_CODEC_ID_PNG,

     .write_header      = mp3_write_header,

     .write_packet      = mp3_write_packet,

     .write_trailer     = mp3_write_trailer,

     .query_codec       = query_codec,

     .flags             = AVFMT_NOTIMESTAMPS,

     .priv_class        = &mp3_muxer_class,

 };
 #endif