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/*

 * 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