/*
  * Windows Television (WTV) muxer
  * Copyright (c) 2011 Zhentan Feng <spyfeng at gmail dot com>
  * Copyright (c) 2011 Peter Ross <pross@xvid.org>
  * 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 <spyfeng at gmail dot com>
  */
 

 #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 void put_videoinfoheader2(AVIOContext *pb, AVStream *st)
 {
     AVRational dar = av_mul_q(st->sample_aspect_ratio, (AVRational){st->codec->width, st->codec->height});
     unsigned int num, den;
     av_reduce(&num, &den, dar.num, dar.den, 0xFFFFFFFF);
 
     /* VIDEOINFOHEADER2 */
     avio_wl32(pb, 0);
     avio_wl32(pb, 0);
     avio_wl32(pb, st->codec->width);
     avio_wl32(pb, st->codec->height);
 
     avio_wl32(pb, 0);
     avio_wl32(pb, 0);
     avio_wl32(pb, 0);
     avio_wl32(pb, 0);
 
     avio_wl32(pb, st->codec->bit_rate);
     avio_wl32(pb, 0);
     avio_wl64(pb, st->avg_frame_rate.num && st->avg_frame_rate.den ? INT64_C(10000000) / av_q2d(st->avg_frame_rate) : 0);
     avio_wl32(pb, 0);
     avio_wl32(pb, 0);
 
     avio_wl32(pb, num);
     avio_wl32(pb, den);
     avio_wl32(pb, 0);
     avio_wl32(pb, 0);
 
     ff_put_bmp_header(pb, st->codec, ff_codec_bmp_tags, 0, 1);
 
     if (st->codec->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
         /* MPEG2VIDEOINFO */
         avio_wl32(pb, 0);
         avio_wl32(pb, st->codec->extradata_size);
         avio_wl32(pb, -1);
         avio_wl32(pb, -1);
         avio_wl32(pb, 0);
         avio_write(pb, st->codec->extradata, st->codec->extradata_size);
         avio_wl64(pb, 0);
     }
 }
 

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

         put_videoinfoheader2(pb, st);

     } 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 },

 };