/*
  * GXF muxer.

  * Copyright (c) 2006 SmartJog S.A., Baptiste Coudurier <baptiste dot coudurier at smartjog dot com>

  *

  * 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 "libavutil/fifo.h"

 #include "avformat.h"
 #include "gxf.h"
 #include "riff.h"

 #include "audiointerleave.h"

 
 #define GXF_AUDIO_PACKET_SIZE 65536
 
 typedef struct GXFStreamContext {

     AudioInterleaveContext aic;

     AVCodecContext *codec;
     uint32_t track_type;
     uint32_t sample_size;
     uint32_t sample_rate;
     uint16_t media_type;
     uint16_t media_info;
     uint8_t index;
     int frame_rate_index;
     int lines_index;
     int fields;
     int iframes;
     int pframes;
     int bframes;
     int p_per_gop;

     int b_per_i_or_p; ///< number of B frames per I frame or P frame

     int first_gop_closed;

     int64_t current_dts;

     int dts_delay;

 } GXFStreamContext;
 
 typedef struct GXFContext {

     uint32_t nb_fields;

     uint32_t material_flags;
     uint16_t audio_tracks;
     uint16_t mpeg_tracks;
     int64_t creation_time;
     uint32_t umf_start_offset;
     uint32_t umf_track_offset;
     uint32_t umf_media_offset;
     uint32_t umf_user_data_offset;
     uint32_t umf_user_data_size;
     uint32_t umf_length;
     uint16_t umf_track_size;
     uint16_t umf_media_size;
     int audio_written;
     int sample_rate;
     int flags;
     AVFormatContext *fc;
 } GXFContext;
 
 typedef struct GXF_Lines {
     int height;
     int index;
 } GXF_Lines;
 
 
 /* FIXME check if it is relevant */
 static const GXF_Lines gxf_lines_tab[] = {
     { 480,  1 }, /* NTSC */
     { 512,  1 }, /* NTSC + VBI */
     { 576,  2 }, /* PAL */
     { 608,  2 }, /* PAL + VBI */
     { 1080, 4 },
     { 720,  6 },
 };
 

 static const AVCodecTag gxf_media_types[] = {

     { CODEC_ID_MJPEG     ,   3 }, /* NTSC */
     { CODEC_ID_MJPEG     ,   4 }, /* PAL */
     { CODEC_ID_PCM_S24LE ,   9 },
     { CODEC_ID_PCM_S16LE ,  10 },
     { CODEC_ID_MPEG2VIDEO,  11 }, /* NTSC */
     { CODEC_ID_MPEG2VIDEO,  12 }, /* PAL */
     { CODEC_ID_DVVIDEO   ,  13 }, /* NTSC */
     { CODEC_ID_DVVIDEO   ,  14 }, /* PAL */
     { CODEC_ID_DVVIDEO   ,  15 }, /* 50M NTSC */
     { CODEC_ID_DVVIDEO   ,  16 }, /* 50M PAL */
     { CODEC_ID_AC3       ,  17 },
     //{ CODEC_ID_NONE,  ,   18 }, /* Non compressed 24 bit audio */
     { CODEC_ID_MPEG2VIDEO,  20 }, /* MPEG HD */
     { CODEC_ID_MPEG1VIDEO,  22 }, /* NTSC */
     { CODEC_ID_MPEG1VIDEO,  23 }, /* PAL */
     { 0, 0 },
 };
 
 #define SERVER_PATH "/space/"
 #define ES_NAME_PATTERN "ES."
 
 static int gxf_find_lines_index(GXFStreamContext *ctx)
 {
     int i;
 
     for (i = 0; i < 6; ++i) {
         if (ctx->codec->height == gxf_lines_tab[i].height) {
             ctx->lines_index = gxf_lines_tab[i].index;
             return 0;
         }
     }
     return -1;
 }
 

 static void gxf_write_padding(ByteIOContext *pb, int64_t to_pad)

 {

     for (; to_pad > 0; to_pad--) {

         put_byte(pb, 0);
     }
 }
 

 static int64_t updatePacketSize(ByteIOContext *pb, int64_t pos)

 {

     int64_t curpos;

     int size;
 
     size = url_ftell(pb) - pos;
     if (size % 4) {
         gxf_write_padding(pb, 4 - size % 4);
         size = url_ftell(pb) - pos;
     }
     curpos = url_ftell(pb);
     url_fseek(pb, pos + 6, SEEK_SET);
     put_be32(pb, size);
     url_fseek(pb, curpos, SEEK_SET);
     return curpos - pos;
 }
 

 static int64_t updateSize(ByteIOContext *pb, int64_t pos)

 {

     int64_t curpos;

 
     curpos = url_ftell(pb);
     url_fseek(pb, pos, SEEK_SET);
     put_be16(pb, curpos - pos - 2);
     url_fseek(pb, curpos, SEEK_SET);
     return curpos - pos;
 }
 

 static void gxf_write_packet_header(ByteIOContext *pb, GXFPktType type)

 {
     put_be32(pb, 0); /* packet leader for synchro */
     put_byte(pb, 1);
     put_byte(pb, type); /* map packet */
     put_be32(pb, 0); /* size */
     put_be32(pb, 0); /* reserved */
     put_byte(pb, 0xE1); /* trailer 1 */
     put_byte(pb, 0xE2); /* trailer 2 */
 }
 
 static int gxf_write_mpeg_auxiliary(ByteIOContext *pb, GXFStreamContext *ctx)
 {
     char buffer[1024];

     int size, starting_line;

 
     if (ctx->iframes) {
         ctx->p_per_gop = ctx->pframes / ctx->iframes;
         if (ctx->pframes % ctx->iframes)
             ctx->p_per_gop++;

         if (ctx->pframes) {

             ctx->b_per_i_or_p = ctx->bframes / ctx->pframes;

             if (ctx->bframes % ctx->pframes)
                 ctx->b_per_i_or_p++;
         }

         if (ctx->p_per_gop > 9)
             ctx->p_per_gop = 9; /* ensure value won't take more than one char */

         if (ctx->b_per_i_or_p > 9)
             ctx->b_per_i_or_p = 9; /* ensure value won't take more than one char */

     }

     if (ctx->codec->height == 512 || ctx->codec->height == 608)
         starting_line = 7; // VBI
     else if (ctx->codec->height == 480)
         starting_line = 20;
     else
         starting_line = 23; // default PAL
 

     size = snprintf(buffer, 1024, "Ver 1\nBr %.6f\nIpg 1\nPpi %d\nBpiop %d\n"

                     "Pix 0\nCf %d\nCg %d\nSl %d\nnl16 %d\nVi 1\nf1 1\n",

                     (float)ctx->codec->bit_rate, ctx->p_per_gop, ctx->b_per_i_or_p,

                     ctx->codec->pix_fmt == PIX_FMT_YUV422P ? 2 : 1, ctx->first_gop_closed == 1,

                     starting_line, ctx->codec->height / 16);

     put_byte(pb, TRACK_MPG_AUX);

     put_byte(pb, size + 1);
     put_buffer(pb, (uint8_t *)buffer, size + 1);
     return size + 3;
 }
 
 static int gxf_write_timecode_auxiliary(ByteIOContext *pb, GXFStreamContext *ctx)
 {
     /* FIXME implement that */
     put_byte(pb, 0); /* fields */
     put_byte(pb, 0);  /* seconds */
     put_byte(pb, 0); /* minutes */
     put_byte(pb, 0); /* flags + hours */
     /* reserved */
     put_be32(pb, 0);
     return 8;
 }
 
 static int gxf_write_track_description(ByteIOContext *pb, GXFStreamContext *stream)
 {

     int64_t pos;

 
     /* track description section */
     put_byte(pb, stream->media_type + 0x80);
     put_byte(pb, stream->index + 0xC0);
 
     pos = url_ftell(pb);
     put_be16(pb, 0); /* size */
 
     /* media file name */

     put_byte(pb, TRACK_NAME);

     put_byte(pb, strlen(ES_NAME_PATTERN) + 3);
     put_tag(pb, ES_NAME_PATTERN);
     put_be16(pb, stream->media_info);
     put_byte(pb, 0);
 
     if (stream->codec->codec_id != CODEC_ID_MPEG2VIDEO) {
         /* auxiliary information */

         put_byte(pb, TRACK_AUX);

         put_byte(pb, 8);
         if (stream->codec->codec_id == CODEC_ID_NONE)
             gxf_write_timecode_auxiliary(pb, stream);
         else
             put_le64(pb, 0);
     }
 
     /* file system version */

     put_byte(pb, TRACK_VER);

     put_byte(pb, 4);
     put_be32(pb, 0);
 
     if (stream->codec->codec_id == CODEC_ID_MPEG2VIDEO)
         gxf_write_mpeg_auxiliary(pb, stream);
 
     /* frame rate */

     put_byte(pb, TRACK_FPS);

     put_byte(pb, 4);
     put_be32(pb, stream->frame_rate_index);
 
     /* lines per frame */

     put_byte(pb, TRACK_LINES);

     put_byte(pb, 4);
     put_be32(pb, stream->lines_index);
 
     /* fields per frame */

     put_byte(pb, TRACK_FPF);

     put_byte(pb, 4);
     put_be32(pb, stream->fields);
 
     return updateSize(pb, pos);
 }
 
 static int gxf_write_material_data_section(ByteIOContext *pb, GXFContext *ctx)
 {

     int64_t pos;

     const char *filename = strrchr(ctx->fc->filename, '/');
 
     pos = url_ftell(pb);
     put_be16(pb, 0); /* size */
 
     /* name */
     if (filename)
         filename++;
     else
         filename = ctx->fc->filename;

     put_byte(pb, MAT_NAME);

     put_byte(pb, strlen(SERVER_PATH) + strlen(filename) + 1);
     put_tag(pb, SERVER_PATH);
     put_tag(pb, filename);
     put_byte(pb, 0);
 
     /* first field */

     put_byte(pb, MAT_FIRST_FIELD);

     put_byte(pb, 4);
     put_be32(pb, 0);
 
     /* last field */

     put_byte(pb, MAT_LAST_FIELD);

     put_byte(pb, 4);

     put_be32(pb, ctx->nb_fields);

 
     /* reserved */

     put_byte(pb, MAT_MARK_IN);

     put_byte(pb, 4);
     put_be32(pb, 0);
 

     put_byte(pb, MAT_MARK_OUT);

     put_byte(pb, 4);

     put_be32(pb, ctx->nb_fields);

 
     /* estimated size */

     put_byte(pb, MAT_SIZE);

     put_byte(pb, 4);
     put_be32(pb, url_fsize(pb) / 1024);
 
     return updateSize(pb, pos);
 }
 
 static int gxf_write_track_description_section(ByteIOContext *pb, GXFContext *ctx)
 {

     int64_t pos;

     int i;
 
     pos = url_ftell(pb);
     put_be16(pb, 0); /* size */
     for (i = 0; i < ctx->fc->nb_streams; ++i)

         gxf_write_track_description(pb, ctx->fc->streams[i]->priv_data);

     return updateSize(pb, pos);
 }
 
 static int gxf_write_map_packet(ByteIOContext *pb, GXFContext *ctx)
 {

     int64_t pos = url_ftell(pb);

 
     gxf_write_packet_header(pb, PKT_MAP);
 
     /* preamble */
     put_byte(pb, 0xE0); /* version */
     put_byte(pb, 0xFF); /* reserved */
 
     gxf_write_material_data_section(pb, ctx);
     gxf_write_track_description_section(pb, ctx);
 
     return updatePacketSize(pb, pos);
 }
 
 #if 0
 static int gxf_write_flt_packet(ByteIOContext *pb, GXFContext *ctx)
 {

     int64_t pos = url_ftell(pb);

     int i;
 
     gxf_write_packet_header(pb, PKT_FLT);
 
     put_le32(pb, 1000); /* number of fields */
     put_le32(pb, 0); /* number of active flt entries */
 
     for (i = 0; i < 1000; ++i) {
         put_le32(pb, 0);
     }
     return updatePacketSize(pb, pos);
 }
 #endif
 
 static int gxf_write_umf_material_description(ByteIOContext *pb, GXFContext *ctx)
 {

     // XXX drop frame
     uint32_t timecode =

         ctx->nb_fields / (ctx->sample_rate * 3600) % 24 << 24 | // hours
         ctx->nb_fields / (ctx->sample_rate * 60) % 60   << 16 | // minutes
         ctx->nb_fields / ctx->sample_rate % 60          <<  8 | // seconds
         ctx->nb_fields % ctx->sample_rate;                    // fields

     put_le32(pb, ctx->flags);

     put_le32(pb, ctx->nb_fields); /* length of the longest track */
     put_le32(pb, ctx->nb_fields); /* length of the shortest track */

     put_le32(pb, 0); /* mark in */

     put_le32(pb, ctx->nb_fields); /* mark out */

     put_le32(pb, 0); /* timecode mark in */

     put_le32(pb, timecode); /* timecode mark out */

     put_le64(pb, ctx->fc->timestamp); /* modification time */
     put_le64(pb, ctx->fc->timestamp); /* creation time */
     put_le16(pb, 0); /* reserved */
     put_le16(pb, 0); /* reserved */
     put_le16(pb, ctx->audio_tracks);
     put_le16(pb, 0); /* timecode track count */
     put_le16(pb, 0); /* reserved */
     put_le16(pb, ctx->mpeg_tracks);
     return 48;
 }
 
 static int gxf_write_umf_payload(ByteIOContext *pb, GXFContext *ctx)
 {
     put_le32(pb, ctx->umf_length); /* total length of the umf data */
     put_le32(pb, 3); /* version */
     put_le32(pb, ctx->fc->nb_streams);
     put_le32(pb, ctx->umf_track_offset); /* umf track section offset */
     put_le32(pb, ctx->umf_track_size);
     put_le32(pb, ctx->fc->nb_streams);
     put_le32(pb, ctx->umf_media_offset);
     put_le32(pb, ctx->umf_media_size);
     put_le32(pb, ctx->umf_user_data_offset); /* user data offset */
     put_le32(pb, ctx->umf_user_data_size); /* user data size */
     put_le32(pb, 0); /* reserved */
     put_le32(pb, 0); /* reserved */
     return 48;
 }
 
 static int gxf_write_umf_track_description(ByteIOContext *pb, GXFContext *ctx)
 {

     int64_t pos = url_ftell(pb);

     int tracks[255]={0};
     int i;
 
     ctx->umf_track_offset = pos - ctx->umf_start_offset;
     for (i = 0; i < ctx->fc->nb_streams; ++i) {
         AVStream *st = ctx->fc->streams[i];

         GXFStreamContext *sc = st->priv_data;

         int id = 0;
 
         switch (st->codec->codec_id) {
         case CODEC_ID_MPEG1VIDEO: id= 'L'; break;
         case CODEC_ID_MPEG2VIDEO: id= 'M'; break;
         case CODEC_ID_PCM_S16LE:  id= 'A'; break;
         case CODEC_ID_DVVIDEO:    id= sc->track_type == 6 ? 'E' : 'D'; break;
         case CODEC_ID_MJPEG:      id= 'V'; break;

         default:                  break;

         }
         sc->media_info= id << 8;
         /* FIXME first 10 audio tracks are 0 to 9 next 22 are A to V */
         sc->media_info |= '0' + (tracks[id]++);
         put_le16(pb, sc->media_info);
         put_le16(pb, 1);
     }
     return url_ftell(pb) - pos;
 }
 
 static int gxf_write_umf_media_mpeg(ByteIOContext *pb, GXFStreamContext *stream)
 {
     if (stream->codec->pix_fmt == PIX_FMT_YUV422P)
         put_le32(pb, 2);
     else
         put_le32(pb, 1); /* default to 420 */

     put_le32(pb, stream->first_gop_closed == 1); /* closed = 1, open = 0, unknown = 255 */

     put_le32(pb, 3); /* top = 1, bottom = 2, frame = 3, unknown = 0 */
     put_le32(pb, 1); /* I picture per GOP */
     put_le32(pb, stream->p_per_gop);

     put_le32(pb, stream->b_per_i_or_p);

     if (stream->codec->codec_id == CODEC_ID_MPEG2VIDEO)
         put_le32(pb, 2);
     else if (stream->codec->codec_id == CODEC_ID_MPEG1VIDEO)
         put_le32(pb, 1);
     else
         put_le32(pb, 0);
     put_le32(pb, 0); /* reserved */
     return 32;
 }
 
 static int gxf_write_umf_media_timecode(ByteIOContext *pb, GXFStreamContext *track)
 {
     /* FIXME implement */
     put_be32(pb, 0); /* drop frame flag */
     put_be32(pb, 0); /* reserved */
     put_be32(pb, 0); /* reserved */
     put_be32(pb, 0); /* reserved */
     put_be32(pb, 0); /* reserved */
     put_be32(pb, 0); /* reserved */
     put_be32(pb, 0); /* reserved */
     put_be32(pb, 0); /* reserved */
     return 32;
 }
 
 static int gxf_write_umf_media_dv(ByteIOContext *pb, GXFStreamContext *track)
 {
     int i;
 
     for (i = 0; i < 8; i++) {
         put_be32(pb, 0);
     }
     return 32;
 }
 
 static int gxf_write_umf_media_audio(ByteIOContext *pb, GXFStreamContext *track)
 {
     put_le64(pb, av_dbl2int(1)); /* sound level to begin to */
     put_le64(pb, av_dbl2int(1)); /* sound level to begin to */
     put_le32(pb, 0); /* number of fields over which to ramp up sound level */
     put_le32(pb, 0); /* number of fields over which to ramp down sound level */
     put_le32(pb, 0); /* reserved */
     put_le32(pb, 0); /* reserved */
     return 32;
 }
 
 #if 0
 static int gxf_write_umf_media_mjpeg(ByteIOContext *pb, GXFStreamContext *track)
 {
     put_be64(pb, 0); /* FIXME FLOAT max chroma quant level */
     put_be64(pb, 0); /* FIXME FLOAT max luma quant level */
     put_be64(pb, 0); /* FIXME FLOAT min chroma quant level */
     put_be64(pb, 0); /* FIXME FLOAT min luma quant level */
     return 32;
 }
 #endif
 
 static int gxf_write_umf_media_description(ByteIOContext *pb, GXFContext *ctx)
 {

     int64_t pos;

     int i;
 
     pos = url_ftell(pb);
     ctx->umf_media_offset = pos - ctx->umf_start_offset;
     for (i = 0; i < ctx->fc->nb_streams; ++i) {

         GXFStreamContext *sc = ctx->fc->streams[i]->priv_data;

         char buffer[88];

         int64_t startpos, curpos;

         int path_size = strlen(ES_NAME_PATTERN);
 

         memset(buffer, 0, 88);

         startpos = url_ftell(pb);
         put_le16(pb, 0); /* length */
         put_le16(pb, sc->media_info);
         put_le16(pb, 0); /* reserved */
         put_le16(pb, 0); /* reserved */

         put_le32(pb, ctx->nb_fields);

         put_le32(pb, 0); /* attributes rw, ro */
         put_le32(pb, 0); /* mark in */

         put_le32(pb, ctx->nb_fields); /* mark out */

         strncpy(buffer, ES_NAME_PATTERN, path_size);
         put_buffer(pb, (uint8_t *)buffer, path_size);
         put_be16(pb, sc->media_info);
         put_buffer(pb, (uint8_t *)buffer + path_size + 2, 88 - path_size - 2);
         put_le32(pb, sc->track_type);
         put_le32(pb, sc->sample_rate);
         put_le32(pb, sc->sample_size);
         put_le32(pb, 0); /* reserved */
         switch (sc->codec->codec_id) {
         case CODEC_ID_MPEG2VIDEO:
             gxf_write_umf_media_mpeg(pb, sc);
             break;
         case CODEC_ID_PCM_S16LE:
             gxf_write_umf_media_audio(pb, sc);
             break;
         case CODEC_ID_DVVIDEO:
             gxf_write_umf_media_dv(pb, sc);
             break;
         default:
             gxf_write_umf_media_timecode(pb, sc); /* 8 0bytes */
         }
         curpos = url_ftell(pb);
         url_fseek(pb, startpos, SEEK_SET);
         put_le16(pb, curpos - startpos);
         url_fseek(pb, curpos, SEEK_SET);
     }
     return url_ftell(pb) - pos;
 }
 
 static int gxf_write_umf_user_data(ByteIOContext *pb, GXFContext *ctx)
 {

     int64_t pos = url_ftell(pb);

     ctx->umf_user_data_offset = pos - ctx->umf_start_offset;
     put_le32(pb, 20);
     put_le32(pb,  0);
     put_le16(pb,  0);
     put_le16(pb,  0);
     put_le32(pb,  0);
     put_byte(pb,  0);
     put_byte(pb,  0);
     put_byte(pb,  0);
     put_byte(pb,  0);
     return 20;
 }
 
 static int gxf_write_umf_packet(ByteIOContext *pb, GXFContext *ctx)
 {

     int64_t pos = url_ftell(pb);

 
     gxf_write_packet_header(pb, PKT_UMF);
 
     /* preamble */
     put_byte(pb, 3); /* first and last (only) packet */
     put_be32(pb, ctx->umf_length); /* data length */
 
     ctx->umf_start_offset = url_ftell(pb);
     gxf_write_umf_payload(pb, ctx);
     gxf_write_umf_material_description(pb, ctx);
     ctx->umf_track_size = gxf_write_umf_track_description(pb, ctx);
     ctx->umf_media_size = gxf_write_umf_media_description(pb, ctx);
     ctx->umf_user_data_size = gxf_write_umf_user_data(pb, ctx);
     ctx->umf_length = url_ftell(pb) - ctx->umf_start_offset;
     return updatePacketSize(pb, pos);
 }
 

 #define GXF_NODELAY -5000
 

 static const int GXF_samples_per_frame[] = { 32768, 0 };
 

 static int gxf_write_header(AVFormatContext *s)
 {

     ByteIOContext *pb = s->pb;

     GXFContext *gxf = s->priv_data;
     int i;
 
     gxf->fc = s;
     gxf->flags |= 0x00080000; /* material is simple clip */
     for (i = 0; i < s->nb_streams; ++i) {
         AVStream *st = s->streams[i];

         GXFStreamContext *sc = av_mallocz(sizeof(*sc));
         if (!sc)
             return AVERROR(ENOMEM);
         st->priv_data = sc;

 
         sc->codec = st->codec;
         sc->index = i;
         sc->media_type = codec_get_tag(gxf_media_types, sc->codec->codec_id);
         if (st->codec->codec_type == CODEC_TYPE_AUDIO) {
             if (st->codec->codec_id != CODEC_ID_PCM_S16LE) {
                 av_log(s, AV_LOG_ERROR, "only 16 BIT PCM LE allowed for now\n");
                 return -1;
             }
             if (st->codec->sample_rate != 48000) {
                 av_log(s, AV_LOG_ERROR, "only 48000hz sampling rate is allowed\n");
                 return -1;
             }
             if (st->codec->channels != 1) {
                 av_log(s, AV_LOG_ERROR, "only mono tracks are allowed\n");
                 return -1;
             }
             sc->track_type = 2;
             sc->sample_rate = st->codec->sample_rate;

             av_set_pts_info(st, 64, 1, sc->sample_rate);

             sc->sample_size = 16;
             sc->frame_rate_index = -2;
             sc->lines_index = -2;
             sc->fields = -2;
             gxf->audio_tracks++;
             gxf->flags |= 0x04000000; /* audio is 16 bit pcm */
         } else if (sc->codec->codec_type == CODEC_TYPE_VIDEO) {
             /* FIXME check from time_base ? */
             if (sc->codec->height == 480 || sc->codec->height == 512) { /* NTSC or NTSC+VBI */
                 sc->frame_rate_index = 5;
                 sc->sample_rate = 60;
                 gxf->flags |= 0x00000080;
             } else { /* assume PAL */
                 sc->frame_rate_index = 6;
                 sc->media_type++;
                 sc->sample_rate = 50;
                 gxf->flags |= 0x00000040;
             }
             gxf->sample_rate = sc->sample_rate;

             av_set_pts_info(st, 64, 1, st->codec->time_base.den);
             sc->dts_delay = GXF_NODELAY;

             if (gxf_find_lines_index(sc) < 0)
                 sc->lines_index = -1;
             sc->sample_size = st->codec->bit_rate;
             sc->fields = 2; /* interlaced */
             switch (sc->codec->codec_id) {
             case CODEC_ID_MPEG2VIDEO:

                 sc->first_gop_closed = -1;

                 sc->track_type = 4;
                 gxf->mpeg_tracks++;
                 gxf->flags |= 0x00008000;
                 break;
             case CODEC_ID_DVVIDEO:
                 if (sc->codec->pix_fmt == PIX_FMT_YUV422P) {
                     sc->media_type += 2;
                     sc->track_type = 6;
                     gxf->flags |= 0x00002000;
                 } else {
                     sc->track_type = 5;
                     gxf->flags |= 0x00001000;
                 }
                 break;
             default:

                 av_log(s, AV_LOG_ERROR, "video codec not supported\n");

                 return -1;
             }
         }
     }

 
     if (ff_audio_interleave_init(s, GXF_samples_per_frame, (AVRational){ 1, 48000 }) < 0)
         return -1;
 

     gxf_write_map_packet(pb, gxf);
     //gxf_write_flt_packet(pb, gxf);
     gxf_write_umf_packet(pb, gxf);
     put_flush_packet(pb);
     return 0;
 }
 
 static int gxf_write_eos_packet(ByteIOContext *pb, GXFContext *ctx)
 {

     int64_t pos = url_ftell(pb);

 
     gxf_write_packet_header(pb, PKT_EOS);
     return updatePacketSize(pb, pos);
 }
 
 static int gxf_write_trailer(AVFormatContext *s)
 {

     ByteIOContext *pb = s->pb;

     GXFContext *gxf = s->priv_data;

     int64_t end;

     ff_audio_interleave_close(s);

 
     gxf_write_eos_packet(pb, gxf);
     end = url_ftell(pb);
     url_fseek(pb, 0, SEEK_SET);
     /* overwrite map and umf packets with new values */
     gxf_write_map_packet(pb, gxf);
     //gxf_write_flt_packet(pb, gxf);
     gxf_write_umf_packet(pb, gxf);
     url_fseek(pb, end, SEEK_SET);
     return 0;
 }
 

 static int gxf_parse_mpeg_frame(GXFStreamContext *sc, const uint8_t *buf, int size)
 {
     uint32_t c=-1;
     int i;
     for(i=0; i<size-4 && c!=0x100; i++){
         c = (c<<8) + buf[i];

         if(c == 0x1B8 && sc->first_gop_closed == -1) /* GOP start code */

             sc->first_gop_closed= (buf[i+4]>>6)&1;

     }
     return (buf[i+1]>>3)&7;
 }
 

 static int gxf_write_media_preamble(ByteIOContext *pb, GXFContext *ctx, AVPacket *pkt, int size)
 {

     GXFStreamContext *sc = ctx->fc->streams[pkt->stream_index]->priv_data;

     unsigned field_nb;
     /* If the video is frame-encoded, the frame numbers shall be represented by
      * even field numbers.
      * see SMPTE360M-2004  6.4.2.1.3 Media field number */
     if (sc->codec->codec_type == CODEC_TYPE_VIDEO) {
         field_nb = ctx->nb_fields;
     } else {
         field_nb = av_rescale_rnd(pkt->dts, ctx->sample_rate, sc->codec->time_base.den, AV_ROUND_UP);
     }

 
     put_byte(pb, sc->media_type);
     put_byte(pb, sc->index);

     put_be32(pb, field_nb);

     if (sc->codec->codec_type == CODEC_TYPE_AUDIO) {
         put_be16(pb, 0);
         put_be16(pb, size / 2);
     } else if (sc->codec->codec_id == CODEC_ID_MPEG2VIDEO) {

         int frame_type = gxf_parse_mpeg_frame(sc, pkt->data, pkt->size);
         if (frame_type == FF_I_TYPE) {

             put_byte(pb, 0x0d);
             sc->iframes++;

         } else if (frame_type == FF_B_TYPE) {

             put_byte(pb, 0x0f);
             sc->bframes++;
         } else {
             put_byte(pb, 0x0e);
             sc->pframes++;
         }
         put_be24(pb, size);
     } else if (sc->codec->codec_id == CODEC_ID_DVVIDEO) {
         put_byte(pb, size / 4096);
         put_be24(pb, 0);
     } else
         put_be32(pb, size);

     put_be32(pb, field_nb);

     put_byte(pb, 1); /* flags */
     put_byte(pb, 0); /* reserved */
     return 16;
 }
 
 static int gxf_write_media_packet(ByteIOContext *pb, GXFContext *ctx, AVPacket *pkt)
 {

     GXFStreamContext *sc = ctx->fc->streams[pkt->stream_index]->priv_data;

     int64_t pos = url_ftell(pb);

     int padding = 0;
 
     gxf_write_packet_header(pb, PKT_MEDIA);
     if (sc->codec->codec_id == CODEC_ID_MPEG2VIDEO && pkt->size % 4) /* MPEG-2 frames must be padded */
         padding = 4 - pkt->size % 4;

     else if (sc->codec->codec_type == CODEC_TYPE_AUDIO)
         padding = GXF_AUDIO_PACKET_SIZE - pkt->size;

     gxf_write_media_preamble(pb, ctx, pkt, pkt->size + padding);

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

     gxf_write_padding(pb, padding);

 
     if (sc->codec->codec_type == CODEC_TYPE_VIDEO)

         ctx->nb_fields += 2; // count fields

     return updatePacketSize(pb, pos);
 }
 
 static int gxf_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     GXFContext *gxf = s->priv_data;
 

     gxf_write_media_packet(s->pb, gxf, pkt);
     put_flush_packet(s->pb);

     return 0;
 }
 
 static int gxf_interleave_packet(AVFormatContext *s, AVPacket *out, AVPacket *pkt, int flush)
 {

     return ff_audio_rechunk_interleave(s, out, pkt, flush,

                                av_interleave_packet_per_dts, ff_interleave_compare_dts);

 }
 
 AVOutputFormat gxf_muxer = {
     "gxf",

     NULL_IF_CONFIG_SMALL("GXF format"),

     NULL,
     "gxf",
     sizeof(GXFContext),
     CODEC_ID_PCM_S16LE,
     CODEC_ID_MPEG2VIDEO,
     gxf_write_header,
     gxf_write_packet,
     gxf_write_trailer,
     0,
     NULL,
     gxf_interleave_packet,
 };