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/*

 * Windows Television (WTV) muxer

 * Copyright (c) 2011 Zhentan Feng 

 * Copyright (c) 2011 Peter Ross 

 * 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

 */

/**

 * @file

 * Windows Television (WTV) demuxer

 * @author Zhentan Feng 

 */

#include "libavutil/intreadwrite.h"

#include "libavutil/avassert.h"

#include "avformat.h"

#include "avio_internal.h"

#include "internal.h"

#include "wtv.h"

#include "asf.h"

#define WTV_BIGSECTOR_SIZE (1 << WTV_BIGSECTOR_BITS)

#define INDEX_BASE 0x2

#define MAX_NB_INDEX 10

/* declare utf16le strings */

#define _ , 0,

static const uint8_t timeline_table_0_header_events[] =

    {'t'_'i'_'m'_'e'_'l'_'i'_'n'_'e'_'.'_'t'_'a'_'b'_'l'_'e'_'.'_'0'_'.'_'h'_'e'_'a'_'d'_'e'_'r'_'.'_'E'_'v'_'e'_'n'_'t'_'s', 0};

static const uint8_t table_0_header_legacy_attrib[] =

    {'t'_'a'_'b'_'l'_'e'_'.'_'0'_'.'_'h'_'e'_'a'_'d'_'e'_'r'_'.'_'l'_'e'_'g'_'a'_'c'_'y'_'_'_'a'_'t'_'t'_'r'_'i'_'b', 0};

static const uint8_t table_0_redirector_legacy_attrib[] =

    {'t'_'a'_'b'_'l'_'e'_'.'_'0'_'.'_'r'_'e'_'d'_'i'_'r'_'e'_'c'_'t'_'o'_'r'_'.'_'l'_'e'_'g'_'a'_'c'_'y'_'_'_'a'_'t'_'t'_'r'_'i'_'b', 0};

static const uint8_t table_0_header_time[] =

    {'t'_'a'_'b'_'l'_'e'_'.'_'0'_'.'_'h'_'e'_'a'_'d'_'e'_'r'_'.'_'t'_'i'_'m'_'e', 0};

static const uint8_t legacy_attrib[] =

    {'l'_'e'_'g'_'a'_'c'_'y'_'_'_'a'_'t'_'t'_'r'_'i'_'b', 0};

#undef _

static const ff_asf_guid sub_wtv_guid =

    {0x8C,0xC3,0xD2,0xC2,0x7E,0x9A,0xDA,0x11,0x8B,0xF7,0x00,0x07,0xE9,0x5E,0xAD,0x8D};

enum WtvFileIndex {

    WTV_TIMELINE_TABLE_0_HEADER_EVENTS = 0,

    WTV_TIMELINE_TABLE_0_ENTRIES_EVENTS,

    WTV_TIMELINE,

    WTV_TABLE_0_HEADER_LEGACY_ATTRIB,

    WTV_TABLE_0_ENTRIES_LEGACY_ATTRIB,

    WTV_TABLE_0_REDIRECTOR_LEGACY_ATTRIB,

    WTV_TABLE_0_HEADER_TIME,

    WTV_TABLE_0_ENTRIES_TIME,

    WTV_FILES

};

typedef struct {

    int64_t length;

    const void *header;

    int depth;

    int first_sector;

} WtvFile;

typedef struct {

    int64_t             pos;

    int64_t             serial;

    const ff_asf_guid * guid;

    int                 stream_id;

} WtvChunkEntry;

typedef struct {

    int64_t serial;

    int64_t value;

} WtvSyncEntry;

typedef struct {

    int64_t timeline_start_pos;

    WtvFile file[WTV_FILES];

    int64_t serial;         /**< chunk serial number */

    int64_t last_chunk_pos; /**< last chunk position */

    int64_t last_timestamp_pos; /**< last timestamp chunk position */

    int64_t first_index_pos;    /**< first index_chunk position */

    WtvChunkEntry index[MAX_NB_INDEX];

    int nb_index;

    int first_video_flag;

    WtvSyncEntry *st_pairs; /* (serial, timestamp) pairs */

    int nb_st_pairs;

    WtvSyncEntry *sp_pairs; /* (serial, position) pairs */

    int nb_sp_pairs;

    int64_t last_pts;

    int64_t last_serial;

    AVPacket thumbnail;

} WtvContext;

static void add_serial_pair(WtvSyncEntry ** list, int * count, int64_t serial, int64_t value)

{

    int new_count = *count + 1;

    WtvSyncEntry *new_list = av_realloc(*list, new_count * sizeof(WtvSyncEntry));

    if (!new_list)

        return;

    new_list[*count] = (WtvSyncEntry){serial, value};

    *list  = new_list;

    *count = new_count;

}

typedef int WTVHeaderWriteFunc(AVIOContext *pb);

typedef struct {

    const uint8_t *header;

    int header_size;

    WTVHeaderWriteFunc *write_header;

} WTVRootEntryTable;

#define write_pad(pb, size) ffio_fill(pb, 0, size)

static const ff_asf_guid *get_codec_guid(enum AVCodecID id, const AVCodecGuid *av_guid)

{

    int i;

    for (i = 0; av_guid[i].id != AV_CODEC_ID_NONE; i++) {

        if (id == av_guid[i].id)

            return &(av_guid[i].guid);

    }

    return NULL;

}

/**

 * Write chunk header. If header chunk (0x80000000 set) then add to list of header chunks

 */

static void write_chunk_header(AVFormatContext *s, const ff_asf_guid *guid, int length, int stream_id)

{

    WtvContext *wctx = s->priv_data;

    AVIOContext *pb = s->pb;

    wctx->last_chunk_pos = avio_tell(pb) - wctx->timeline_start_pos;

    ff_put_guid(pb, guid);

    avio_wl32(pb, 32 + length);

    avio_wl32(pb, stream_id);

    avio_wl64(pb, wctx->serial);

    if ((stream_id & 0x80000000) && guid != &ff_index_guid) {

        WtvChunkEntry *t = wctx->index + wctx->nb_index;

        av_assert0(wctx->nb_index < MAX_NB_INDEX);

        t->pos       = wctx->last_chunk_pos;

        t->serial    = wctx->serial;

        t->guid      = guid;

        t->stream_id = stream_id & 0x3FFFFFFF;

        wctx->nb_index++;

    }

}

static void write_chunk_header2(AVFormatContext *s, const ff_asf_guid *guid, int stream_id)

{

    WtvContext *wctx = s->priv_data;

    AVIOContext *pb = s->pb;

    int64_t last_chunk_pos = wctx->last_chunk_pos;

    write_chunk_header(s, guid, 0, stream_id); // length updated later

    avio_wl64(pb, last_chunk_pos);

}

static void finish_chunk_noindex(AVFormatContext *s)

{

    WtvContext *wctx = s->priv_data;

    AVIOContext *pb = s->pb;

    // update the chunk_len field and pad.

    int64_t chunk_len = avio_tell(pb) - (wctx->last_chunk_pos + wctx->timeline_start_pos);

    avio_seek(pb, -(chunk_len - 16), SEEK_CUR);

    avio_wl32(pb, chunk_len);

    avio_seek(pb, chunk_len - (16 + 4), SEEK_CUR);

    write_pad(pb, WTV_PAD8(chunk_len) - chunk_len);

    wctx->serial++;

}

static void write_index(AVFormatContext *s)

{

    AVIOContext *pb = s->pb;

    WtvContext *wctx = s->priv_data;

    int i;

    write_chunk_header2(s, &ff_index_guid, 0x80000000);

    avio_wl32(pb, 0);

    avio_wl32(pb, 0);

    for (i = 0; i < wctx->nb_index; i++) {

        WtvChunkEntry *t = wctx->index + i;

        ff_put_guid(pb,  t->guid);

        avio_wl64(pb, t->pos);

        avio_wl32(pb, t->stream_id);

        avio_wl32(pb, 0); // checksum?

        avio_wl64(pb, t->serial);

    }

    wctx->nb_index = 0;   // reset index

    finish_chunk_noindex(s);

    if (!wctx->first_index_pos)

        wctx->first_index_pos = wctx->last_chunk_pos;

}

static void finish_chunk(AVFormatContext *s)

{

    WtvContext *wctx = s->priv_data;

    finish_chunk_noindex(s);

    if (wctx->nb_index == MAX_NB_INDEX)

        write_index(s);

}

static int write_stream_codec_info(AVFormatContext *s, AVStream *st)

{

    WtvContext *wctx = s->priv_data;

    const ff_asf_guid *g, *media_type, *format_type;

    AVIOContext *pb = s->pb;

    int64_t  hdr_pos_start;

    int hdr_size = 0;

    if (st->codec->codec_type  == AVMEDIA_TYPE_VIDEO) {

        g = get_codec_guid(st->codec->codec_id, ff_video_guids);

        media_type = &ff_mediatype_video;

        format_type = &ff_format_mpeg2_video;

    } else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {

        g = get_codec_guid(st->codec->codec_id, ff_codec_wav_guids);

        media_type = &ff_mediatype_audio;

        format_type = &ff_format_waveformatex;

    } else {

        av_log(s, AV_LOG_ERROR, "unknown codec_type (0x%x)\n", st->codec->codec_type);

        return -1;

    }

    if (g == NULL) {

        av_log(s, AV_LOG_ERROR, "can't get video codec_id (0x%x) guid.\n", st->codec->codec_id);

        return -1;

    }

    ff_put_guid(pb, media_type); // mediatype

    ff_put_guid(pb, &ff_mediasubtype_cpfilters_processed); // subtype

    write_pad(pb, 12);

    ff_put_guid(pb,&ff_format_cpfilters_processed); // format type

    avio_wl32(pb, 0); // size

    hdr_pos_start = avio_tell(pb);

    if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {

        if (wctx->first_video_flag) {

            write_pad(pb, 216); //The size is sensitive.

            wctx->first_video_flag = 0;

        } else {

            write_pad(pb, 72); // aspect ratio

            ff_put_bmp_header(pb, st->codec, ff_codec_bmp_tags, 0);

        }

    } else {

        ff_put_wav_header(pb, st->codec);

    }

    hdr_size = avio_tell(pb) - hdr_pos_start;

    // seek back write hdr_size

    avio_seek(pb, -(hdr_size + 4), SEEK_CUR);

    avio_wl32(pb, hdr_size + 32);

    avio_seek(pb, hdr_size, SEEK_CUR);

    ff_put_guid(pb, g);           // actual_subtype

    ff_put_guid(pb, format_type); // actual_formattype

    return 0;

}

static int write_stream_codec(AVFormatContext *s, AVStream * st)

{

    AVIOContext *pb = s->pb;

    int ret;

    write_chunk_header2(s, &ff_stream1_guid, 0x80000000 | 0x01);

    avio_wl32(pb,  0x01);

    write_pad(pb, 4);

    write_pad(pb, 4);

    ret = write_stream_codec_info(s, st);

    if (ret < 0) {

        av_log(s, AV_LOG_ERROR, "write stream codec info failed codec_type(0x%x)\n", st->codec->codec_type);

        return -1;

    }

    finish_chunk(s);

    return 0;

}

static void write_sync(AVFormatContext *s)

{

    AVIOContext *pb = s->pb;

    WtvContext *wctx = s->priv_data;

    int64_t last_chunk_pos = wctx->last_chunk_pos;

    write_chunk_header(s, &ff_sync_guid, 0x18, 0);

    avio_wl64(pb, wctx->first_index_pos);

    avio_wl64(pb, wctx->last_timestamp_pos);

    avio_wl64(pb, 0);

    finish_chunk(s);

    add_serial_pair(&wctx->sp_pairs, &wctx->nb_sp_pairs, wctx->serial, wctx->last_chunk_pos);

    wctx->last_chunk_pos = last_chunk_pos;

}

static int write_stream_data(AVFormatContext *s, AVStream *st)

{

    AVIOContext *pb = s->pb;

    int ret;

    write_chunk_header2(s, &ff_SBE2_STREAM_DESC_EVENT, 0x80000000 | (st->index + INDEX_BASE));

    avio_wl32(pb, 0x00000001);

    avio_wl32(pb, st->index + INDEX_BASE); //stream_id

    avio_wl32(pb, 0x00000001);

    write_pad(pb, 8);

    ret = write_stream_codec_info(s, st);

    if (ret < 0) {

        av_log(s, AV_LOG_ERROR, "write stream codec info failed codec_type(0x%x)\n", st->codec->codec_type);

        return -1;

    }

    finish_chunk(s);

    avpriv_set_pts_info(st, 64, 1, 10000000);

    return 0;

}

static int write_header(AVFormatContext *s)

{

    AVIOContext *pb = s->pb;

    WtvContext *wctx = s->priv_data;

    int i, pad, ret;

    AVStream *st;

    wctx->last_chunk_pos     = -1;

    wctx->last_timestamp_pos = -1;

    ff_put_guid(pb, &ff_wtv_guid);

    ff_put_guid(pb, &sub_wtv_guid);

    avio_wl32(pb, 0x01);

    avio_wl32(pb, 0x02);

    avio_wl32(pb, 1 << WTV_SECTOR_BITS);

    avio_wl32(pb, 1 << WTV_BIGSECTOR_BITS);

    //write initial root fields

    avio_wl32(pb, 0); // root_size, update later

    write_pad(pb, 4);

    avio_wl32(pb, 0); // root_sector, update it later.

    write_pad(pb, 32);

    avio_wl32(pb, 0); // file ends pointer, update it later.

    pad = (1 << WTV_SECTOR_BITS) - avio_tell(pb);

    write_pad(pb, pad);

    wctx->timeline_start_pos = avio_tell(pb);

    wctx->serial = 1;

    wctx->last_chunk_pos = -1;

    wctx->first_video_flag = 1;

    for (i = 0; i < s->nb_streams; i++) {

        st = s->streams[i];

        if (st->codec->codec_id == AV_CODEC_ID_MJPEG)

            continue;

        ret = write_stream_codec(s, st);

        if (ret < 0) {

            av_log(s, AV_LOG_ERROR, "write stream codec failed codec_type(0x%x)\n", st->codec->codec_type);

            return -1;

        }

        if (!i)

            write_sync(s);

    }

    for (i = 0; i < s->nb_streams; i++) {

        st = s->streams[i];

        if (st->codec->codec_id == AV_CODEC_ID_MJPEG)

            continue;

        ret  = write_stream_data(s, st);

        if (ret < 0) {

            av_log(s, AV_LOG_ERROR, "write stream data failed codec_type(0x%x)\n", st->codec->codec_type);

            return -1;

        }

    }

    if (wctx->nb_index)

        write_index(s);

    return 0;

}

static void write_timestamp(AVFormatContext *s, AVPacket *pkt)

{

    AVIOContext *pb = s->pb;

    WtvContext  *wctx = s->priv_data;

    AVCodecContext *enc = s->streams[pkt->stream_index]->codec;

    write_chunk_header(s, &ff_timestamp_guid, 56, 0x40000000 | (INDEX_BASE + pkt->stream_index));

    write_pad(pb, 8);

    avio_wl64(pb, pkt->pts == AV_NOPTS_VALUE ? -1 : pkt->pts);

    avio_wl64(pb, pkt->pts == AV_NOPTS_VALUE ? -1 : pkt->pts);

    avio_wl64(pb, pkt->pts == AV_NOPTS_VALUE ? -1 : pkt->pts);

    avio_wl64(pb, 0);

    avio_wl64(pb, enc->codec_type == AVMEDIA_TYPE_VIDEO && (pkt->flags & AV_PKT_FLAG_KEY) ? 1 : 0);

    avio_wl64(pb, 0);

    wctx->last_timestamp_pos = wctx->last_chunk_pos;

}

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

{

    AVIOContext *pb = s->pb;

    WtvContext  *wctx = s->priv_data;

    if (s->streams[pkt->stream_index]->codec->codec_id == AV_CODEC_ID_MJPEG && !wctx->thumbnail.size) {

        av_copy_packet(&wctx->thumbnail, pkt);

        return 0;

    }

    /* emit sync chunk and 'timeline.table.0.entries.Event' record every 50 frames */

    if (wctx->serial - (wctx->nb_sp_pairs ? wctx->sp_pairs[wctx->nb_sp_pairs - 1].serial : 0) >= 50)

        write_sync(s);

    /* emit 'table.0.entries.time' record every 500ms */

    if (pkt->pts != AV_NOPTS_VALUE && pkt->pts - (wctx->nb_st_pairs ? wctx->st_pairs[wctx->nb_st_pairs - 1].value : 0) >= 5000000)

        add_serial_pair(&wctx->st_pairs, &wctx->nb_st_pairs, wctx->serial, pkt->pts);

    if (pkt->pts != AV_NOPTS_VALUE && pkt->pts > wctx->last_pts) {

        wctx->last_pts = pkt->pts;

        wctx->last_serial = wctx->serial;

    }

    // write timestamp chunk

    write_timestamp(s, pkt);

    write_chunk_header(s, &ff_data_guid, pkt->size, INDEX_BASE + pkt->stream_index);

    avio_write(pb, pkt->data, pkt->size);

    write_pad(pb, WTV_PAD8(pkt->size) - pkt->size);

    wctx->serial++;

    return 0;

}

static int write_table0_header_events(AVIOContext *pb)

{

    avio_wl32(pb, 0x10);

    write_pad(pb, 84);

    avio_wl64(pb, 0x32);

    return 96;

}

static int write_table0_header_legacy_attrib(AVIOContext *pb)

{

    int pad = 0;

    avio_wl32(pb, 0xFFFFFFFF);

    write_pad(pb, 12);

    avio_write(pb, legacy_attrib, sizeof(legacy_attrib));

    pad = WTV_PAD8(sizeof(legacy_attrib)) - sizeof(legacy_attrib);

    write_pad(pb, pad);

    write_pad(pb, 32);

    return 48 + WTV_PAD8(sizeof(legacy_attrib));

}

static int write_table0_header_time(AVIOContext *pb)

{

    avio_wl32(pb, 0x10);

    write_pad(pb, 76);

    avio_wl64(pb, 0x40);

    return 88;

}

static const WTVRootEntryTable wtv_root_entry_table[] = {

    { timeline_table_0_header_events,          sizeof(timeline_table_0_header_events),          write_table0_header_events},

    { ff_timeline_table_0_entries_Events_le16, sizeof(ff_timeline_table_0_entries_Events_le16), NULL},

    { ff_timeline_le16,                        sizeof(ff_timeline_le16),                        NULL},

    { table_0_header_legacy_attrib,            sizeof(table_0_header_legacy_attrib),            write_table0_header_legacy_attrib},

    { ff_table_0_entries_legacy_attrib_le16,   sizeof(ff_table_0_entries_legacy_attrib_le16),   NULL},

    { table_0_redirector_legacy_attrib,        sizeof(table_0_redirector_legacy_attrib),        NULL},

    { table_0_header_time,                     sizeof(table_0_header_time),                     write_table0_header_time},

    { ff_table_0_entries_time_le16,            sizeof(ff_table_0_entries_time_le16),            NULL},

};

static int write_root_table(AVFormatContext *s, int64_t sector_pos)

{

    AVIOContext *pb = s->pb;

    WtvContext  *wctx = s->priv_data;

    int size, pad;

    int i;

    const WTVRootEntryTable *h = wtv_root_entry_table;

    for (i = 0; i < sizeof(wtv_root_entry_table)/sizeof(WTVRootEntryTable); i++, h++) {

        WtvFile *w = &wctx->file[i];

        int filename_padding = WTV_PAD8(h->header_size) - h->header_size;

        WTVHeaderWriteFunc *write = h->write_header;

        int len = 0;

        int64_t len_pos;

        ff_put_guid(pb, &ff_dir_entry_guid);

        len_pos = avio_tell(pb);

        avio_wl16(pb, 40 + h->header_size + filename_padding + 8); // maybe updated later

        write_pad(pb, 6);

        avio_wl64(pb, write ? 0 : w->length);// maybe update later

        avio_wl32(pb, (h->header_size + filename_padding) >> 1);

        write_pad(pb, 4);

        avio_write(pb, h->header, h->header_size);

        write_pad(pb, filename_padding);

        if (write) {

            len = write(pb);

            // update length field

            avio_seek(pb, len_pos, SEEK_SET);

            avio_wl64(pb, 40 + h->header_size + filename_padding + len);

            avio_wl64(pb, len |(1ULL<<62) | (1ULL<<60));

            avio_seek(pb, 8 + h->header_size + filename_padding + len, SEEK_CUR);

        } else {

            avio_wl32(pb, w->first_sector);

            avio_wl32(pb, w->depth);

        }

    }

    // caculate root table size

    size = avio_tell(pb) - sector_pos;

    pad = WTV_SECTOR_SIZE- size;

    write_pad(pb, pad);

    return size;

}

static void write_fat(AVIOContext *pb, int start_sector, int nb_sectors, int shift)

{

    int i;

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

        avio_wl32(pb, start_sector + (i << shift));

    }

    // pad left sector pointer size

    write_pad(pb, WTV_SECTOR_SIZE - ((nb_sectors << 2) % WTV_SECTOR_SIZE));

}

static int64_t write_fat_sector(AVFormatContext *s, int64_t start_pos, int nb_sectors, int sector_bits, int depth)

{

    int64_t start_sector = start_pos >> WTV_SECTOR_BITS;

    int shift = sector_bits - WTV_SECTOR_BITS;

    int64_t fat = avio_tell(s->pb);

    write_fat(s->pb, start_sector, nb_sectors, shift);

    if (depth == 2) {

        int64_t start_sector1 = fat >> WTV_SECTOR_BITS;

        int nb_sectors1 = ((nb_sectors << 2) + WTV_SECTOR_SIZE - 1) / WTV_SECTOR_SIZE;

        int64_t fat1 = avio_tell(s->pb);

       write_fat(s->pb, start_sector1, nb_sectors1, 0);

       return fat1;

    }

    return fat;

}

static void write_table_entries_events(AVFormatContext *s)

{

    AVIOContext *pb = s->pb;

    WtvContext *wctx = s->priv_data;

    int i;

    for (i = 0; i < wctx->nb_sp_pairs; i++) {

        avio_wl64(pb, wctx->sp_pairs[i].serial);

        avio_wl64(pb, wctx->sp_pairs[i].value);

    }

}

static void write_table_entries_time(AVFormatContext *s)

{

    AVIOContext *pb = s->pb;

    WtvContext *wctx = s->priv_data;

    int i;

    for (i = 0; i < wctx->nb_st_pairs; i++) {

        avio_wl64(pb, wctx->st_pairs[i].value);

        avio_wl64(pb, wctx->st_pairs[i].serial);

    }

    avio_wl64(pb, wctx->last_pts);

    avio_wl64(pb, wctx->last_serial);

}

static void write_metadata_header(AVIOContext *pb, int type, const char *key, int value_size)

{

    ff_put_guid(pb, &ff_metadata_guid);

    avio_wl32(pb, type);

    avio_wl32(pb, value_size);

    avio_put_str16le(pb, key);

}

static int metadata_header_size(const char *key)

{

    return 16 + 4 + 4 + strlen(key)*2 + 2;

}

static void write_tag_int32(AVIOContext *pb, const char *key, int value)

{

    write_metadata_header(pb, 0, key, 4);

    avio_wl32(pb, value);

}

static void write_tag(AVIOContext *pb, const char *key, const char *value)

{

    write_metadata_header(pb, 1, key, strlen(value)*2 + 2);

    avio_put_str16le(pb, value);

}

static int attachment_value_size(const AVPacket *pkt, const AVDictionaryEntry *e)

{

    return strlen("image/jpeg")*2 + 2 + 1 + (e ? strlen(e->value)*2 : 0) + 2 + 4 + pkt->size;

}

static void write_table_entries_attrib(AVFormatContext *s)

{

    WtvContext *wctx = s->priv_data;

    AVIOContext *pb = s->pb;

    AVDictionaryEntry *tag = 0;

    //FIXME: translate special tags (e.g. WM/Bitrate) to binary representation

    ff_metadata_conv(&s->metadata, ff_asf_metadata_conv, NULL);

    while ((tag = av_dict_get(s->metadata, "", tag, AV_DICT_IGNORE_SUFFIX)))

        write_tag(pb, tag->key, tag->value);

    if (wctx->thumbnail.size) {

        AVStream *st = s->streams[wctx->thumbnail.stream_index];

        tag = av_dict_get(st->metadata, "title", NULL, 0);

        write_metadata_header(pb, 2, "WM/Picture", attachment_value_size(&wctx->thumbnail, tag));

        avio_put_str16le(pb, "image/jpeg");

        avio_w8(pb, 0x10);

        avio_put_str16le(pb, tag ? tag->value : "");

        avio_wl32(pb, wctx->thumbnail.size);

        avio_write(pb, wctx->thumbnail.data, wctx->thumbnail.size);

        write_tag_int32(pb, "WM/MediaThumbType", 2);

    }

}

static void write_table_redirector_legacy_attrib(AVFormatContext *s)

{

    WtvContext *wctx = s->priv_data;

    AVIOContext *pb = s->pb;

    AVDictionaryEntry *tag = 0;

    int64_t pos = 0;

    //FIXME: translate special tags to binary representation

    while ((tag = av_dict_get(s->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {

        avio_wl64(pb, pos);

        pos += metadata_header_size(tag->key) + strlen(tag->value)*2 + 2;

    }

    if (wctx->thumbnail.size) {

        AVStream *st = s->streams[wctx->thumbnail.stream_index];

        avio_wl64(pb, pos);

        pos += metadata_header_size("WM/Picture") + attachment_value_size(&wctx->thumbnail, av_dict_get(st->metadata, "title", NULL, 0));

        avio_wl64(pb, pos);

        pos += metadata_header_size("WM/MediaThumbType") + 4;

    }

}

/**

 * Pad the remainder of a file

 * Write out fat table

 * @return <0 on error

 */

static int finish_file(AVFormatContext *s, enum WtvFileIndex index, int64_t start_pos)

{

    WtvContext *wctx = s->priv_data;

    AVIOContext *pb = s->pb;

    WtvFile *w = &wctx->file[index];

    int64_t end_pos = avio_tell(pb);

    int sector_bits, nb_sectors, pad;

    av_assert0(index < WTV_FILES);

    w->length = (end_pos - start_pos);

    // determine optimal fat table depth, sector_bits, nb_sectors

    if (w->length <= WTV_SECTOR_SIZE) {

        w->depth = 0;

        sector_bits = WTV_SECTOR_BITS;

    } else if (w->length <= (WTV_SECTOR_SIZE / 4) * WTV_SECTOR_SIZE) {

        w->depth = 1;

        sector_bits = WTV_SECTOR_BITS;

    } else if (w->length <= (WTV_SECTOR_SIZE / 4) * WTV_BIGSECTOR_SIZE) {

        w->depth = 1;

        sector_bits = WTV_BIGSECTOR_BITS;

    } else if (w->length <= (int64_t)(WTV_SECTOR_SIZE / 4) * (WTV_SECTOR_SIZE / 4) * WTV_SECTOR_SIZE) {

        w->depth = 2;

        sector_bits = WTV_SECTOR_BITS;

    } else if (w->length <= (int64_t)(WTV_SECTOR_SIZE / 4) * (WTV_SECTOR_SIZE / 4) * WTV_BIGSECTOR_SIZE) {

        w->depth = 2;

        sector_bits = WTV_BIGSECTOR_BITS;

    } else {

        av_log(s, AV_LOG_ERROR, "unsupported file allocation table depth (%"PRIi64" bytes)\n", w->length);

        return -1;

    }

    // determine the nb_sectors

    nb_sectors = (int)(w->length >> sector_bits);

    // pad sector of timeline

    pad = (1 << sector_bits) - (w->length % (1 << sector_bits));

    if (pad) {

        nb_sectors++;

        write_pad(pb, pad);

    }

    //write fat table

    if (w->depth > 0) {

        w->first_sector = write_fat_sector(s, start_pos, nb_sectors, sector_bits, w->depth) >> WTV_SECTOR_BITS;

    } else {

        w->first_sector = start_pos >> WTV_SECTOR_BITS;

    }

    w->length |= 1ULL<<60;

    if (sector_bits == WTV_SECTOR_BITS)

        w->length |= 1ULL<<63;

    return 0;

}

static int write_trailer(AVFormatContext *s)

{

    WtvContext *wctx = s->priv_data;

    AVIOContext *pb = s->pb;

    int root_size;

    int64_t sector_pos;

    int64_t start_pos, file_end_pos;

    if (finish_file(s, WTV_TIMELINE, wctx->timeline_start_pos) < 0)

        return -1;

    start_pos = avio_tell(pb);

    write_table_entries_events(s);

    if (finish_file(s, WTV_TIMELINE_TABLE_0_ENTRIES_EVENTS, start_pos) < 0)

        return -1;

    start_pos = avio_tell(pb);

    write_table_entries_attrib(s);

    if (finish_file(s, WTV_TABLE_0_ENTRIES_LEGACY_ATTRIB, start_pos) < 0)

        return -1;

    start_pos = avio_tell(pb);

    write_table_redirector_legacy_attrib(s);

    if (finish_file(s, WTV_TABLE_0_REDIRECTOR_LEGACY_ATTRIB, start_pos) < 0)

        return -1;

    start_pos = avio_tell(pb);

    write_table_entries_time(s);

    if (finish_file(s, WTV_TABLE_0_ENTRIES_TIME, start_pos) < 0)

        return -1;

    // write root table

    sector_pos = avio_tell(pb);

    root_size = write_root_table(s, sector_pos);

    file_end_pos = avio_tell(pb);

    // update root value

    avio_seek(pb, 0x30, SEEK_SET);

    avio_wl32(pb, root_size);

    avio_seek(pb, 4, SEEK_CUR);

    avio_wl32(pb, sector_pos >> WTV_SECTOR_BITS);

    avio_seek(pb, 0x5c, SEEK_SET);

    avio_wl32(pb, file_end_pos >> WTV_SECTOR_BITS);

    avio_flush(pb);

    av_free(wctx->sp_pairs);

    av_free(wctx->st_pairs);

    av_free_packet(&wctx->thumbnail);

    return 0;

}

AVOutputFormat ff_wtv_muxer = {

    .name           = "wtv",

    .long_name      = NULL_IF_CONFIG_SMALL("Windows Television (WTV)"),

    .extensions     = "wtv",

    .priv_data_size = sizeof(WtvContext),

    .audio_codec    = AV_CODEC_ID_AC3,

    .video_codec    = AV_CODEC_ID_MPEG2VIDEO,

    .write_header   = write_header,

    .write_packet   = write_packet,

    .write_trailer  = write_trailer,

    .codec_tag      = (const AVCodecTag* const []){ ff_codec_bmp_tags,

                                                    ff_codec_wav_tags, 0 },

};