/*
  * GXF demuxer.

  * Copyright (c) 2006 Reimar Doeffinger

  *

  * 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 <inttypes.h>
 

 #include "libavutil/channel_layout.h"

 #include "libavutil/common.h"

 #include "avformat.h"

 #include "internal.h"

 #include "gxf.h"

 #include "libavcodec/mpeg12data.h"

 struct gxf_stream_info {

     int64_t first_field;
     int64_t last_field;
     AVRational frames_per_second;
     int32_t fields_per_frame;

     int64_t track_aux_data;

 };

 /**

  * @brief parse gxf timecode and add it to metadata
  */
 static int add_timecode_metadata(AVDictionary **pm, const char *key, uint32_t timecode, int fields_per_frame)
 {
    char tmp[128];
    int field  = timecode & 0xff;
    int frame  = fields_per_frame ? field / fields_per_frame : field;
    int second = (timecode >>  8) & 0xff;
    int minute = (timecode >> 16) & 0xff;
    int hour   = (timecode >> 24) & 0x1f;
    int drop   = (timecode >> 29) & 1;
    // bit 30: color_frame, unused
    // ignore invalid time code
    if (timecode >> 31)
        return 0;
    snprintf(tmp, sizeof(tmp), "%02d:%02d:%02d%c%02d",
        hour, minute, second, drop ? ';' : ':', frame);
    return av_dict_set(pm, key, tmp, 0);
 }
 
 /**

  * @brief parses a packet header, extracting type and length
  * @param pb AVIOContext to read header from
  * @param type detected packet type is stored here
  * @param length detected packet length, excluding header is stored here
  * @return 0 if header not found or contains invalid data, 1 otherwise

  */

 static int parse_packet_header(AVIOContext *pb, GXFPktType *type, int *length) {

     if (avio_rb32(pb))

         return 0;

     if (avio_r8(pb) != 1)

         return 0;

     *type = avio_r8(pb);
     *length = avio_rb32(pb);

     if ((*length >> 24) || *length < 16)
         return 0;
     *length -= 16;

     if (avio_rb32(pb))

         return 0;

     if (avio_r8(pb) != 0xe1)

         return 0;

     if (avio_r8(pb) != 0xe2)

         return 0;
     return 1;
 }
 
 /**

  * @brief check if file starts with a PKT_MAP header

  */
 static int gxf_probe(AVProbeData *p) {
     static const uint8_t startcode[] = {0, 0, 0, 0, 1, 0xbc}; // start with map packet
     static const uint8_t endcode[] = {0, 0, 0, 0, 0xe1, 0xe2};
     if (!memcmp(p->buf, startcode, sizeof(startcode)) &&
         !memcmp(&p->buf[16 - sizeof(endcode)], endcode, sizeof(endcode)))
         return AVPROBE_SCORE_MAX;
     return 0;
 }
 
 /**

  * @brief gets the stream index for the track with the specified id, creates new

  *        stream if not found

  * @param id     id of stream to find / add
  * @param format stream format identifier

  */
 static int get_sindex(AVFormatContext *s, int id, int format) {
     int i;
     AVStream *st = NULL;

     i = ff_find_stream_index(s, id);
     if (i >= 0)
         return i;

     st = avformat_new_stream(s, NULL);

     if (!st)
         return AVERROR(ENOMEM);

     st->id = id;

     switch (format) {
         case 3:
         case 4:

             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

             st->codec->codec_id = AV_CODEC_ID_MJPEG;

             break;
         case 13:
         case 14:

         case 15:

         case 16:

         case 25:

             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

             st->codec->codec_id = AV_CODEC_ID_DVVIDEO;

             break;
         case 11:
         case 12:
         case 20:

             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

             st->codec->codec_id = AV_CODEC_ID_MPEG2VIDEO;

             st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.

             break;
         case 22:
         case 23:

             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

             st->codec->codec_id = AV_CODEC_ID_MPEG1VIDEO;

             st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.

             break;
         case 9:

             st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

             st->codec->codec_id = AV_CODEC_ID_PCM_S24LE;

             st->codec->channels = 1;

             st->codec->channel_layout = AV_CH_LAYOUT_MONO;

             st->codec->sample_rate = 48000;
             st->codec->bit_rate = 3 * 1 * 48000 * 8;
             st->codec->block_align = 3 * 1;

             st->codec->bits_per_coded_sample = 24;

             break;
         case 10:

             st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

             st->codec->codec_id = AV_CODEC_ID_PCM_S16LE;

             st->codec->channels = 1;

             st->codec->channel_layout = AV_CH_LAYOUT_MONO;

             st->codec->sample_rate = 48000;
             st->codec->bit_rate = 2 * 1 * 48000 * 8;
             st->codec->block_align = 2 * 1;

             st->codec->bits_per_coded_sample = 16;

             break;
         case 17:

             st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

             st->codec->codec_id = AV_CODEC_ID_AC3;

             st->codec->channels = 2;

             st->codec->channel_layout = AV_CH_LAYOUT_STEREO;

             st->codec->sample_rate = 48000;
             break;

         case 26: /* AVCi50 / AVCi100 (AVC Intra) */

         case 29: /* AVCHD */

             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

             st->codec->codec_id = AV_CODEC_ID_H264;

             st->need_parsing = AVSTREAM_PARSE_HEADERS;
             break;

         // timecode tracks:
         case 7:
         case 8:
         case 24:

             st->codec->codec_type = AVMEDIA_TYPE_DATA;

             st->codec->codec_id = AV_CODEC_ID_NONE;

             break;

         case 30:
             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
             st->codec->codec_id = AV_CODEC_ID_DNXHD;
             break;

         default:

             st->codec->codec_type = AVMEDIA_TYPE_UNKNOWN;

             st->codec->codec_id = AV_CODEC_ID_NONE;

             break;
     }
     return s->nb_streams - 1;
 }
 

 /**

  * @brief filters out interesting tags from material information.
  * @param len length of tag section, will be adjusted to contain remaining bytes
  * @param si struct to store collected information into

  */

 static void gxf_material_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si) {

     si->first_field = AV_NOPTS_VALUE;
     si->last_field = AV_NOPTS_VALUE;
     while (*len >= 2) {

         GXFMatTag tag = avio_r8(pb);
         int tlen = avio_r8(pb);

         *len -= 2;
         if (tlen > *len)
             return;
         *len -= tlen;
         if (tlen == 4) {

             uint32_t value = avio_rb32(pb);

             if (tag == MAT_FIRST_FIELD)
                 si->first_field = value;
             else if (tag == MAT_LAST_FIELD)
                 si->last_field = value;
         } else

             avio_skip(pb, tlen);

     }
 }
 

 static const AVRational frame_rate_tab[] = {
     {   60,    1},
     {60000, 1001},
     {   50,    1},
     {   30,    1},
     {30000, 1001},
     {   25,    1},
     {   24,    1},
     {24000, 1001},
     {    0,    0},
 };
 

 /**

  * @brief convert fps tag value to AVRational fps
  * @param fps fps value from tag
  * @return fps as AVRational, or 0 / 0 if unknown

  */
 static AVRational fps_tag2avr(int32_t fps) {
     if (fps < 1 || fps > 9) fps = 9;

     return frame_rate_tab[fps - 1];

 }
 
 /**

  * @brief convert UMF attributes flags to AVRational fps
  * @param flags UMF flags to convert
  * @return fps as AVRational, or 0 / 0 if unknown

  */
 static AVRational fps_umf2avr(uint32_t flags) {
     static const AVRational map[] = {{50, 1}, {60000, 1001}, {24, 1},
         {25, 1}, {30000, 1001}};
     int idx =  av_log2((flags & 0x7c0) >> 6);
     return map[idx];
 }
 
 /**

  * @brief filters out interesting tags from track information.
  * @param len length of tag section, will be adjusted to contain remaining bytes
  * @param si struct to store collected information into

  */

 static void gxf_track_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si) {

     si->frames_per_second = (AVRational){0, 0};
     si->fields_per_frame = 0;

     si->track_aux_data = 0x80000000;

     while (*len >= 2) {

         GXFTrackTag tag = avio_r8(pb);
         int tlen = avio_r8(pb);

         *len -= 2;
         if (tlen > *len)
             return;
         *len -= tlen;
         if (tlen == 4) {

             uint32_t value = avio_rb32(pb);

             if (tag == TRACK_FPS)
                 si->frames_per_second = fps_tag2avr(value);
             else if (tag == TRACK_FPF && (value == 1 || value == 2))
                 si->fields_per_frame = value;

         } else if (tlen == 8 && tag == TRACK_AUX)
             si->track_aux_data = avio_rl64(pb);
         else

             avio_skip(pb, tlen);

     }
 }
 
 /**

  * @brief read index from FLT packet into stream 0 av_index

  */
 static void gxf_read_index(AVFormatContext *s, int pkt_len) {

     AVIOContext *pb = s->pb;

     AVStream *st;

     uint32_t fields_per_map = avio_rl32(pb);
     uint32_t map_cnt = avio_rl32(pb);

     int i;
     pkt_len -= 8;

     if ((s->flags & AVFMT_FLAG_IGNIDX) || !s->streams) {

         avio_skip(pb, pkt_len);

         return;
     }

     st = s->streams[0];

     if (map_cnt > 1000) {

         av_log(s, AV_LOG_ERROR,
                "too many index entries %"PRIu32" (%"PRIx32")\n",
                map_cnt, map_cnt);

         map_cnt = 1000;
     }
     if (pkt_len < 4 * map_cnt) {

         av_log(s, AV_LOG_ERROR, "invalid index length\n");

         avio_skip(pb, pkt_len);

         return;
     }
     pkt_len -= 4 * map_cnt;
     av_add_index_entry(st, 0, 0, 0, 0, 0);
     for (i = 0; i < map_cnt; i++)

         av_add_index_entry(st, (uint64_t)avio_rl32(pb) * 1024,

                            i * (uint64_t)fields_per_map + 1, 0, 0, 0);

     avio_skip(pb, pkt_len);

 }
 

 static int gxf_header(AVFormatContext *s) {

     AVIOContext *pb = s->pb;

     GXFPktType pkt_type;

     int map_len;
     int len;

     AVRational main_timebase = {0, 0};

     struct gxf_stream_info *si = s->priv_data;

     int i;

     if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {

         av_log(s, AV_LOG_ERROR, "map packet not found\n");

         return 0;
     }
     map_len -= 2;

     if (avio_r8(pb) != 0x0e0 || avio_r8(pb) != 0xff) {

         av_log(s, AV_LOG_ERROR, "unknown version or invalid map preamble\n");

         return 0;
     }
     map_len -= 2;

     len = avio_rb16(pb); // length of material data section

     if (len > map_len) {

         av_log(s, AV_LOG_ERROR, "material data longer than map data\n");

         return 0;
     }
     map_len -= len;

     gxf_material_tags(pb, &len, si);

     avio_skip(pb, len);

     map_len -= 2;

     len = avio_rb16(pb); // length of track description

     if (len > map_len) {

         av_log(s, AV_LOG_ERROR, "track description longer than map data\n");

         return 0;
     }
     map_len -= len;
     while (len > 0) {
         int track_type, track_id, track_len;

         AVStream *st;
         int idx;

         len -= 4;

         track_type = avio_r8(pb);
         track_id = avio_r8(pb);
         track_len = avio_rb16(pb);

         len -= track_len;
         if (!(track_type & 0x80)) {

            av_log(s, AV_LOG_ERROR, "invalid track type %x\n", track_type);

            continue;
         }
         track_type &= 0x7f;
         if ((track_id & 0xc0) != 0xc0) {

            av_log(s, AV_LOG_ERROR, "invalid track id %x\n", track_id);

            continue;
         }
         track_id &= 0x3f;

         gxf_track_tags(pb, &track_len, si);
         // check for timecode tracks
         if (track_type == 7 || track_type == 8 || track_type == 24) {

             add_timecode_metadata(&s->metadata, "timecode",

                                   si->track_aux_data & 0xffffffff,
                                   si->fields_per_frame);
 
         }
         avio_skip(pb, track_len);
 

         idx = get_sindex(s, track_id, track_type);
         if (idx < 0) continue;
         st = s->streams[idx];
         if (!main_timebase.num || !main_timebase.den) {

             main_timebase.num = si->frames_per_second.den;
             main_timebase.den = si->frames_per_second.num * 2;

         }

         st->start_time = si->first_field;
         if (si->first_field != AV_NOPTS_VALUE && si->last_field != AV_NOPTS_VALUE)
             st->duration = si->last_field - si->first_field;

     }
     if (len < 0)

         av_log(s, AV_LOG_ERROR, "invalid track description length specified\n");

     if (map_len)

         avio_skip(pb, map_len);

     if (!parse_packet_header(pb, &pkt_type, &len)) {

         av_log(s, AV_LOG_ERROR, "sync lost in header\n");

         return -1;
     }
     if (pkt_type == PKT_FLT) {
         gxf_read_index(s, len);
         if (!parse_packet_header(pb, &pkt_type, &len)) {

             av_log(s, AV_LOG_ERROR, "sync lost in header\n");

             return -1;
         }
     }
     if (pkt_type == PKT_UMF) {

         if (len >= 0x39) {

             AVRational fps;

             len -= 0x39;

             avio_skip(pb, 5); // preamble
             avio_skip(pb, 0x30); // payload description

             fps = fps_umf2avr(avio_rl32(pb));

             if (!main_timebase.num || !main_timebase.den) {

                 av_log(s, AV_LOG_WARNING, "No FPS track tag, using UMF fps tag."
                                           " This might give wrong results.\n");

                 // this may not always be correct, but simply the best we can get
                 main_timebase.num = fps.den;

                 main_timebase.den = fps.num * 2;

             }

 
             if (len >= 0x18) {
                 len -= 0x18;
                 avio_skip(pb, 0x10);

                 add_timecode_metadata(&s->metadata, "timecode_at_mark_in",

                                       avio_rl32(pb), si->fields_per_frame);

                 add_timecode_metadata(&s->metadata, "timecode_at_mark_out",

                                       avio_rl32(pb), si->fields_per_frame);
             }

         } else

             av_log(s, AV_LOG_INFO, "UMF packet too short\n");

     } else

         av_log(s, AV_LOG_INFO, "UMF packet missing\n");

     avio_skip(pb, len);

     // set a fallback value, 60000/1001 is specified for audio-only files
     // so use that regardless of why we do not know the video frame rate.

     if (!main_timebase.num || !main_timebase.den)

         main_timebase = (AVRational){1001, 60000};

     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st = s->streams[i];

         avpriv_set_pts_info(st, 32, main_timebase.num, main_timebase.den);

     }

     return 0;
 }
 

 #define READ_ONE() \
     { \

         if (!max_interval-- || avio_feof(pb)) \

             goto out; \

         tmp = tmp << 8 | avio_r8(pb); \

     }
 
 /**

  * @brief resync the stream on the next media packet with specified properties
  * @param max_interval how many bytes to search for matching packet at most
  * @param track track id the media packet must belong to, -1 for any
  * @param timestamp minimum timestamp (== field number) the packet must have, -1 for any
  * @return timestamp of packet found

  */
 static int64_t gxf_resync_media(AVFormatContext *s, uint64_t max_interval, int track, int timestamp) {
     uint32_t tmp;
     uint64_t last_pos;
     uint64_t last_found_pos = 0;
     int cur_track;
     int64_t cur_timestamp = AV_NOPTS_VALUE;
     int len;

     AVIOContext *pb = s->pb;

     GXFPktType type;

     tmp = avio_rb32(pb);

 start:
     while (tmp)
         READ_ONE();
     READ_ONE();
     if (tmp != 1)
         goto start;

     last_pos = avio_tell(pb);

     if (avio_seek(pb, -5, SEEK_CUR) < 0)

         goto out;

     if (!parse_packet_header(pb, &type, &len) || type != PKT_MEDIA) {

         if (avio_seek(pb, last_pos, SEEK_SET) < 0)

             goto out;

         goto start;
     }

     avio_r8(pb);
     cur_track = avio_r8(pb);
     cur_timestamp = avio_rb32(pb);

     last_found_pos = avio_tell(pb) - 16 - 6;

     if ((track >= 0 && track != cur_track) || (timestamp >= 0 && timestamp > cur_timestamp)) {

         if (avio_seek(pb, last_pos, SEEK_SET) >= 0)

             goto start;

     }
 out:
     if (last_found_pos)

         avio_seek(pb, last_found_pos, SEEK_SET);

     return cur_timestamp;
 }
 

 static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {

     AVIOContext *pb = s->pb;

     GXFPktType pkt_type;

     int pkt_len;

     struct gxf_stream_info *si = s->priv_data;
 

     while (!pb->eof_reached) {

         AVStream *st;

         int track_type, track_id, ret;

         int field_nr, field_info, skip = 0;

         int stream_index;

         if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {

             if (!avio_feof(pb))

                 av_log(s, AV_LOG_ERROR, "sync lost\n");

             return -1;
         }

         if (pkt_type == PKT_FLT) {
             gxf_read_index(s, pkt_len);
             continue;
         }

         if (pkt_type != PKT_MEDIA) {

             avio_skip(pb, pkt_len);

             continue;
         }
         if (pkt_len < 16) {

             av_log(s, AV_LOG_ERROR, "invalid media packet length\n");

             continue;
         }
         pkt_len -= 16;

         track_type = avio_r8(pb);
         track_id = avio_r8(pb);

         stream_index = get_sindex(s, track_id, track_type);
         if (stream_index < 0)
             return stream_index;

         st = s->streams[stream_index];

         field_nr = avio_rb32(pb);
         field_info = avio_rb32(pb);
         avio_rb32(pb); // "timeline" field number
         avio_r8(pb); // flags
         avio_r8(pb); // reserved

         if (st->codec->codec_id == AV_CODEC_ID_PCM_S24LE ||
             st->codec->codec_id == AV_CODEC_ID_PCM_S16LE) {

             int first = field_info >> 16;
             int last  = field_info & 0xffff; // last is exclusive
             int bps = av_get_bits_per_sample(st->codec->codec_id)>>3;
             if (first <= last && last*bps <= pkt_len) {

                 avio_skip(pb, first*bps);

                 skip = pkt_len - last*bps;
                 pkt_len = (last-first)*bps;
             } else
                 av_log(s, AV_LOG_ERROR, "invalid first and last sample values\n");
         }

         ret = av_get_packet(pb, pkt, pkt_len);

         if (skip)

             avio_skip(pb, skip);

         pkt->stream_index = stream_index;

         pkt->dts = field_nr;

 
         //set duration manually for DV or else lavf misdetects the frame rate

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

             pkt->duration = si->fields_per_frame;
 

         return ret;
     }

     return AVERROR_EOF;

 }
 

 static int gxf_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {

     int64_t res = 0;

     uint64_t pos;
     uint64_t maxlen = 100 * 1024 * 1024;
     AVStream *st = s->streams[0];
     int64_t start_time = s->streams[stream_index]->start_time;
     int64_t found;
     int idx;
     if (timestamp < start_time) timestamp = start_time;
     idx = av_index_search_timestamp(st, timestamp - start_time,
                                     AVSEEK_FLAG_ANY | AVSEEK_FLAG_BACKWARD);
     if (idx < 0)
         return -1;
     pos = st->index_entries[idx].pos;
     if (idx < st->nb_index_entries - 2)
         maxlen = st->index_entries[idx + 2].pos - pos;
     maxlen = FFMAX(maxlen, 200 * 1024);

     res = avio_seek(s->pb, pos, SEEK_SET);

     if (res < 0)
         return res;

     found = gxf_resync_media(s, maxlen, -1, timestamp);

     if (FFABS(found - timestamp) > 4)

         return -1;
     return 0;
 }
 
 static int64_t gxf_read_timestamp(AVFormatContext *s, int stream_index,
                                   int64_t *pos, int64_t pos_limit) {

     AVIOContext *pb = s->pb;

     int64_t res;

     if (avio_seek(pb, *pos, SEEK_SET) < 0)

         return AV_NOPTS_VALUE;

     res = gxf_resync_media(s, pos_limit - *pos, -1, -1);

     *pos = avio_tell(pb);

     return res;
 }
 

 AVInputFormat ff_gxf_demuxer = {

     .name           = "gxf",

     .long_name      = NULL_IF_CONFIG_SMALL("GXF (General eXchange Format)"),

     .priv_data_size = sizeof(struct gxf_stream_info),
     .read_probe     = gxf_probe,
     .read_header    = gxf_header,
     .read_packet    = gxf_packet,
     .read_seek      = gxf_seek,
     .read_timestamp = gxf_read_timestamp,

 };