/*
  * 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"

 #include "libavutil/crc.h"
 #include "libavutil/mathematics.h"
 #include "libavutil/replaygain.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, "TDRC",    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

 // size of the XING/LAME data, starting from the Xing tag
 #define XING_SIZE 156

 typedef struct MP3Context {
     const AVClass *class;

     ID3v2EncContext id3;

     int id3v2_version;

     int write_id3v1;

     int write_xing;

 
     /* xing header */

     // a buffer containing the whole XING/LAME frame
     uint8_t *xing_frame;
     int      xing_frame_size;
 
     AVCRC    audio_crc;     // CRC of the audio data
     uint32_t audio_size;    // total size of the audio data
 
     // offset of the XING/LAME frame in the file
     int64_t  xing_frame_offset;
     // offset of the XING/INFO tag in the frame
     int 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;

     AVDictionaryEntry *enc = av_dict_get(s->streams[mp3->audio_stream_idx]->metadata, "encoder", NULL, 0);
     AVIOContext *dyn_ctx;

     int32_t        header;
     MPADecodeHeader  mpah;
     int srate_idx, i, channels;

     int bitrate_idx;

     int best_bitrate_idx = -1;

     int best_bitrate_error = INT_MAX;

     int ret;

     int ver = 0;

     int bytes_needed;

     if (!s->pb->seekable || !mp3->write_xing)

         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 bit_rate = 1000 * avpriv_mpa_bitrate_tab[ver != 3][3 - 1][bitrate_idx];

         int error    = FFABS(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++) {

         int32_t mask = bitrate_idx << (4 + 8);

         if (15 == bitrate_idx)
             return -1;

         header |= mask;

 
         avpriv_mpegaudio_decode_header(&mpah, header);

         mp3->xing_offset = xing_offtbl[mpah.lsf == 1][mpah.nb_channels == 1] + 4;
         bytes_needed     = mp3->xing_offset + XING_SIZE;

         if (bytes_needed <= mpah.frame_size)

             break;

         header &= ~mask;

     }
 

     ret = avio_open_dyn_buf(&dyn_ctx);
     if (ret < 0)

         return ret;

 
     avio_wb32(dyn_ctx, header);

     ffio_fill(dyn_ctx, 0, mp3->xing_offset - 4);
     ffio_wfourcc(dyn_ctx, "Xing");
     avio_wb32(dyn_ctx, 0x01 | 0x02 | 0x04 | 0x08);  // frames / size / TOC / vbr scale

     mp3->size = mpah.frame_size;

     mp3->want=1;
     mp3->seen=0;
     mp3->pos=0;

     avio_wb32(dyn_ctx, 0);  // frames
     avio_wb32(dyn_ctx, 0);  // size

 
     // TOC
     for (i = 0; i < XING_TOC_SIZE; i++)

         avio_w8(dyn_ctx, (uint8_t)(255 * i / XING_TOC_SIZE));

 
     // vbr quality
     // we write it, because some (broken) tools always expect it to be present
     avio_wb32(dyn_ctx, 0);
 
     // encoder short version string
     if (enc) {
         uint8_t encoder_str[9] = { 0 };

         if (   strlen(enc->value) > sizeof(encoder_str)
             && !strcmp("Lavc libmp3lame", enc->value)) {
             memcpy(encoder_str, "Lavf lame", 9);
         } else
             memcpy(encoder_str, enc->value, FFMIN(strlen(enc->value), sizeof(encoder_str)));
 

         avio_write(dyn_ctx, encoder_str, sizeof(encoder_str));
     } else

         avio_write(dyn_ctx, "Lavf\0\0\0\0\0", 9);

 
     avio_w8(dyn_ctx, 0);      // tag revision 0 / unknown vbr method
     avio_w8(dyn_ctx, 0);      // unknown lowpass filter value
     ffio_fill(dyn_ctx, 0, 8); // empty replaygain fields
     avio_w8(dyn_ctx, 0);      // unknown encoding flags
     avio_w8(dyn_ctx, 0);      // unknown abr/minimal bitrate
 
     // encoder delay

     if (codec->initial_padding - 528 - 1 >= 1 << 12) {

         av_log(s, AV_LOG_WARNING, "Too many samples of initial padding.\n");
     }

     avio_wb24(dyn_ctx, FFMAX(codec->initial_padding - 528 - 1, 0)<<12);

 
     avio_w8(dyn_ctx,   0); // misc
     avio_w8(dyn_ctx,   0); // mp3gain
     avio_wb16(dyn_ctx, 0); // preset
 
     // audio length and CRCs (will be updated later)
     avio_wb32(dyn_ctx, 0); // music length
     avio_wb16(dyn_ctx, 0); // music crc
     avio_wb16(dyn_ctx, 0); // tag crc

     ffio_fill(dyn_ctx, 0, mpah.frame_size - bytes_needed);

     mp3->xing_frame_size   = avio_close_dyn_buf(dyn_ctx, &mp3->xing_frame);
     mp3->xing_frame_offset = avio_tell(s->pb);
     avio_write(s->pb, mp3->xing_frame, mp3->xing_frame_size);

     mp3->audio_size = mp3->xing_frame_size;

 
     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 mpah;

         int av_unused base;

         uint32_t h;
 
         h = AV_RB32(pkt->data);
         if (ff_mpa_check_header(h) == 0) {

             avpriv_mpegaudio_decode_header(&mpah, h);

             if (!mp3->initial_bitrate)

                 mp3->initial_bitrate = mpah.bit_rate;
             if ((mpah.bit_rate == 0) || (mp3->initial_bitrate != mpah.bit_rate))

                 mp3->has_variable_bitrate = 1;

         } else {

             av_log(s, AV_LOG_WARNING, "Audio packet of size %d (starting with %08X...) "

                    "is invalid, writing it anyway.\n", pkt->size, h);

         }

 #ifdef FILTER_VBR_HEADERS

         /* filter out XING and INFO headers. */

         base = 4 + xing_offtbl[mpah.lsf == 1][mpah.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);

             mp3->audio_size += pkt->size;
             mp3->audio_crc   = av_crc(av_crc_get_table(AV_CRC_16_ANSI_LE),
                                       mp3->audio_crc, pkt->data, pkt->size);
         }

     }

 
     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, s->metadata_header_padding);

     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;

     AVReplayGain *rg;
     uint16_t tag_crc;
     uint8_t *toc;
     int i, rg_size;

 
     /* replace "Xing" identification string with "Info" for CBR files. */

     if (!mp3->has_variable_bitrate)
         AV_WL32(mp3->xing_frame + mp3->xing_offset, MKTAG('I', 'n', 'f', 'o'));

     AV_WB32(mp3->xing_frame + mp3->xing_offset + 8,  mp3->frames);
     AV_WB32(mp3->xing_frame + mp3->xing_offset + 12, mp3->size);

     toc    = mp3->xing_frame + mp3->xing_offset + 16;
     toc[0] = 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;

         toc[i] = FFMIN(seek_point, 255);

     }
 

     /* write replaygain */
     rg = (AVReplayGain*)av_stream_get_side_data(s->streams[0], AV_PKT_DATA_REPLAYGAIN,
                                                 &rg_size);
     if (rg && rg_size >= sizeof(*rg)) {
         uint16_t val;
 
         AV_WB32(mp3->xing_frame + mp3->xing_offset + 131,
                 av_rescale(rg->track_peak, 1 << 23, 100000));
 
         if (rg->track_gain != INT32_MIN) {
             val  = FFABS(rg->track_gain / 10000) & ((1 << 9) - 1);
             val |= (rg->track_gain < 0) << 9;
             val |= 1 << 13;
             AV_WB16(mp3->xing_frame + mp3->xing_offset + 135, val);
         }
 
         if (rg->album_gain != INT32_MIN) {
             val  = FFABS(rg->album_gain / 10000) & ((1 << 9) - 1);
             val |= (rg->album_gain < 0) << 9;
             val |= 1 << 14;
             AV_WB16(mp3->xing_frame + mp3->xing_offset + 137, val);
         }
     }
 
     AV_WB32(mp3->xing_frame + mp3->xing_offset + XING_SIZE - 8, mp3->audio_size);
     AV_WB16(mp3->xing_frame + mp3->xing_offset + XING_SIZE - 4, mp3->audio_crc);
 
     tag_crc = av_crc(av_crc_get_table(AV_CRC_16_ANSI_LE), 0, mp3->xing_frame, 190);
     AV_WB16(mp3->xing_frame + mp3->xing_offset + XING_SIZE - 2, tag_crc);
 
     avio_seek(s->pb,  mp3->xing_frame_offset, SEEK_SET);
     avio_write(s->pb, mp3->xing_frame, mp3->xing_frame_size);

     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);

     av_freep(&mp3->xing_frame);
 

     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/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}, 0, 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},

     { "write_xing",  "Write the Xing header containing file duration.",
       offsetof(MP3Context, write_xing),  AV_OPT_TYPE_INT, {.i64 = 1}, 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));

             int ret;

             if (!pktl) {
                 av_log(s, AV_LOG_WARNING, "Not enough memory to buffer audio. Skipping picture streams\n");
                 mp3->pics_to_write = 0;
                 mp3_queue_flush(s);
                 return mp3_write_audio_packet(s, pkt);
             }

             ret = av_copy_packet(&pktl->pkt, pkt);
             if (ret < 0) {

                 av_freep(&pktl);

                 return ret;

             }

 
             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;

     if (mp3->id3v2_version      &&
         mp3->id3v2_version != 3 &&
         mp3->id3v2_version != 4) {
         av_log(s, AV_LOG_ERROR, "Invalid ID3v2 version requested: %d. Only "
                "3, 4 or 0 (disabled) are allowed.\n", mp3->id3v2_version);
         return AVERROR(EINVAL);
     }
 

     /* 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;
 

     if (mp3->pics_to_write && !mp3->id3v2_version) {
         av_log(s, AV_LOG_ERROR, "Attached pictures were requested, but the "
                "ID3v2 header is disabled.\n");
         return AVERROR(EINVAL);
     }
 
     if (mp3->id3v2_version) {
         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) {

         if (mp3->id3v2_version)

             ff_id3v2_finish(&mp3->id3, s->pb, s->metadata_header_padding);

         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/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