text: /*
   * LXF demuxer
   * Copyright (c) 2010 Tomas Härdin
   *
   * 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/intreadwrite.h"
  #include "libavcodec/bytestream.h"
  #include "avformat.h"
  #include "internal.h"
  
  #define LXF_MAX_PACKET_HEADER_SIZE 256
  #define LXF_HEADER_DATA_SIZE    120
  #define LXF_IDENT               "LEITCH\0"
  #define LXF_IDENT_LENGTH        8
  #define LXF_SAMPLERATE          48000
  
  static const AVCodecTag lxf_tags[] = {
      { AV_CODEC_ID_MJPEG,       0 },
      { AV_CODEC_ID_MPEG1VIDEO,  1 },
      { AV_CODEC_ID_MPEG2VIDEO,  2 },    //MpMl, 4:2:0
      { AV_CODEC_ID_MPEG2VIDEO,  3 },    //MpPl, 4:2:2
      { AV_CODEC_ID_DVVIDEO,     4 },    //DV25
      { AV_CODEC_ID_DVVIDEO,     5 },    //DVCPRO
      { AV_CODEC_ID_DVVIDEO,     6 },    //DVCPRO50
      { AV_CODEC_ID_RAWVIDEO,    7 },    //AV_PIX_FMT_ARGB, where alpha is used for chroma keying
      { AV_CODEC_ID_RAWVIDEO,    8 },    //16-bit chroma key
      { AV_CODEC_ID_MPEG2VIDEO,  9 },    //4:2:2 CBP ("Constrained Bytes per Gop")
      { AV_CODEC_ID_NONE,        0 },
  };
  
  typedef struct LXFDemuxContext {
      int channels;                       ///< number of audio channels. zero means no audio
      int frame_number;                   ///< current video frame
      uint32_t video_format, packet_type, extended_size;
  } LXFDemuxContext;
  
  static int lxf_probe(AVProbeData *p)
  {
      if (!memcmp(p->buf, LXF_IDENT, LXF_IDENT_LENGTH))
          return AVPROBE_SCORE_MAX;
  
      return 0;
  }
  
  /**
   * Verify the checksum of an LXF packet header
   *
   * @param[in] header the packet header to check
   * @return zero if the checksum is OK, non-zero otherwise
   */
  static int check_checksum(const uint8_t *header, int size)
  {
      int x;
      uint32_t sum = 0;
  
      for (x = 0; x < size; x += 4)
          sum += AV_RL32(&header[x]);
  
      return sum;
  }
  
  /**
   * Read input until we find the next ident. If found, copy it to the header buffer
   *
   * @param[out] header where to copy the ident to
   * @return 0 if an ident was found, < 0 on I/O error
   */
  static int lxf_sync(AVFormatContext *s, uint8_t *header)
  {
      uint8_t buf[LXF_IDENT_LENGTH];
      int ret;
  
      if ((ret = avio_read(s->pb, buf, LXF_IDENT_LENGTH)) != LXF_IDENT_LENGTH)
          return ret < 0 ? ret : AVERROR_EOF;
  
      while (memcmp(buf, LXF_IDENT, LXF_IDENT_LENGTH)) {
          if (avio_feof(s->pb))
              return AVERROR_EOF;
  
          memmove(buf, &buf[1], LXF_IDENT_LENGTH-1);
          buf[LXF_IDENT_LENGTH-1] = avio_r8(s->pb);
      }
  
      memcpy(header, LXF_IDENT, LXF_IDENT_LENGTH);
  
      return 0;
  }
  
  /**
   * Read and checksum the next packet header
   *
   * @return the size of the payload following the header or < 0 on failure
   */
  static int get_packet_header(AVFormatContext *s)
  {
      LXFDemuxContext *lxf = s->priv_data;
      AVIOContext   *pb  = s->pb;
      int track_size, samples, ret;
      uint32_t version, audio_format, header_size, channels, tmp;
      AVStream *st;
      uint8_t header[LXF_MAX_PACKET_HEADER_SIZE];
      const uint8_t *p = header + LXF_IDENT_LENGTH;
  
      //find and read the ident
      if ((ret = lxf_sync(s, header)) < 0)
          return ret;
  
      ret = avio_read(pb, header + LXF_IDENT_LENGTH, 8);
      if (ret != 8)
          return ret < 0 ? ret : AVERROR_EOF;
  
      version     = bytestream_get_le32(&p);
      header_size = bytestream_get_le32(&p);
      if (version > 1)
          avpriv_request_sample(s, "Unknown format version %"PRIu32"\n", version);
  
      if (header_size < (version ? 72 : 60) ||
          header_size > LXF_MAX_PACKET_HEADER_SIZE ||
          (header_size & 3)) {
          av_log(s, AV_LOG_ERROR, "Invalid header size 0x%"PRIx32"\n", header_size);
          return AVERROR_INVALIDDATA;
      }
  
      //read the rest of the packet header
      if ((ret = avio_read(pb, header + (p - header),
                            header_size - (p - header))) !=
                            header_size - (p - header))
          return ret < 0 ? ret : AVERROR_EOF;
  
      if (check_checksum(header, header_size))
          av_log(s, AV_LOG_ERROR, "checksum error\n");
  
      lxf->packet_type = bytestream_get_le32(&p);
      p += version ? 20 : 12;
  
      lxf->extended_size = 0;
      switch (lxf->packet_type) {
      case 0:
          //video
          lxf->video_format = bytestream_get_le32(&p);
          ret               = bytestream_get_le32(&p);
          //skip VBI data and metadata
          avio_skip(pb, (int64_t)(uint32_t)AV_RL32(p + 4) +
                        (int64_t)(uint32_t)AV_RL32(p + 12));
          break;
      case 1:
          //audio
          if (s->nb_streams < 2) {
              av_log(s, AV_LOG_INFO, "got audio packet, but no audio stream present\n");
              break;
          }
  
          if (version == 0)
              p += 8;
          audio_format = bytestream_get_le32(&p);
          channels     = bytestream_get_le32(&p);
          track_size   = bytestream_get_le32(&p);
  
          st = s->streams[1];
  
          //set codec based on specified audio bitdepth
          //we only support tightly packed 16-, 20-, 24- and 32-bit PCM at the moment
          st->codec->bits_per_coded_sample = (audio_format >> 6) & 0x3F;
  
          if (st->codec->bits_per_coded_sample != (audio_format & 0x3F)) {
              av_log(s, AV_LOG_WARNING, "only tightly packed PCM currently supported\n");
              return AVERROR_PATCHWELCOME;
          }
  
          switch (st->codec->bits_per_coded_sample) {
          case 16: st->codec->codec_id = AV_CODEC_ID_PCM_S16LE_PLANAR; break;
          case 20: st->codec->codec_id = AV_CODEC_ID_PCM_LXF;   break;
          case 24: st->codec->codec_id = AV_CODEC_ID_PCM_S24LE_PLANAR; break;
          case 32: st->codec->codec_id = AV_CODEC_ID_PCM_S32LE_PLANAR; break;
          default:
              av_log(s, AV_LOG_WARNING,
                     "only 16-, 20-, 24- and 32-bit PCM currently supported\n");
              return AVERROR_PATCHWELCOME;
          }
  
          samples = track_size * 8 / st->codec->bits_per_coded_sample;
  
          //use audio packet size to determine video standard
          //for NTSC we have one 8008-sample audio frame per five video frames
          if (samples == LXF_SAMPLERATE * 5005 / 30000) {
              avpriv_set_pts_info(s->streams[0], 64, 1001, 30000);
          } else {
              //assume PAL, but warn if we don't have 1920 samples
              if (samples != LXF_SAMPLERATE / 25)
                  av_log(s, AV_LOG_WARNING,
                         "video doesn't seem to be PAL or NTSC. guessing PAL\n");
  
              avpriv_set_pts_info(s->streams[0], 64, 1, 25);
          }
  
          //TODO: warning if track mask != (1 << channels) - 1?
          ret = av_popcount(channels) * track_size;
  
          break;
      default:
          tmp = bytestream_get_le32(&p);
          ret = bytestream_get_le32(&p);
          if (tmp == 1)
              lxf->extended_size = bytestream_get_le32(&p);
          break;
      }
  
      return ret;
  }
  
  static int lxf_read_header(AVFormatContext *s)
  {
      LXFDemuxContext *lxf = s->priv_data;
      AVIOContext   *pb  = s->pb;
      uint8_t header_data[LXF_HEADER_DATA_SIZE];
      int ret;
      AVStream *st;
      uint32_t video_params, disk_params;
      uint16_t record_date, expiration_date;
  
      if ((ret = get_packet_header(s)) < 0)
          return ret;
  
      if (ret != LXF_HEADER_DATA_SIZE) {
          av_log(s, AV_LOG_ERROR, "expected %d B size header, got %d\n",
                 LXF_HEADER_DATA_SIZE, ret);
          return AVERROR_INVALIDDATA;
      }
  
      if ((ret = avio_read(pb, header_data, LXF_HEADER_DATA_SIZE)) != LXF_HEADER_DATA_SIZE)
          return ret < 0 ? ret : AVERROR_EOF;
  
      if (!(st = avformat_new_stream(s, NULL)))
          return AVERROR(ENOMEM);
  
      st->duration          = AV_RL32(&header_data[32]);
      video_params          = AV_RL32(&header_data[40]);
      record_date           = AV_RL16(&header_data[56]);
      expiration_date       = AV_RL16(&header_data[58]);
      disk_params           = AV_RL32(&header_data[116]);
  
      st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
      st->codec->bit_rate   = 1000000 * ((video_params >> 14) & 0xFF);
      st->codec->codec_tag  = video_params & 0xF;
      st->codec->codec_id   = ff_codec_get_id(lxf_tags, st->codec->codec_tag);
      st->need_parsing      = AVSTREAM_PARSE_HEADERS;
  
      av_log(s, AV_LOG_DEBUG, "record: %x = %i-%02i-%02i\n",
             record_date, 1900 + (record_date & 0x7F), (record_date >> 7) & 0xF,
             (record_date >> 11) & 0x1F);
  
      av_log(s, AV_LOG_DEBUG, "expire: %x = %i-%02i-%02i\n",
             expiration_date, 1900 + (expiration_date & 0x7F), (expiration_date >> 7) & 0xF,
             (expiration_date >> 11) & 0x1F);
  
      if ((video_params >> 22) & 1)
          av_log(s, AV_LOG_WARNING, "VBI data not yet supported\n");
  
      if ((lxf->channels = 1 << (disk_params >> 4 & 3) + 1)) {
          if (!(st = avformat_new_stream(s, NULL)))
              return AVERROR(ENOMEM);
  
          st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;
          st->codec->sample_rate = LXF_SAMPLERATE;
          st->codec->channels    = lxf->channels;
  
          avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
      }
  
      avio_skip(s->pb, lxf->extended_size);
  
      return 0;
  }
  
  static int lxf_read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      LXFDemuxContext *lxf = s->priv_data;
      AVIOContext   *pb  = s->pb;
      uint32_t stream;
      int ret, ret2;
  
      if ((ret = get_packet_header(s)) < 0)
          return ret;
  
      stream = lxf->packet_type;
  
      if (stream > 1) {
          av_log(s, AV_LOG_WARNING,
                 "got packet with illegal stream index %"PRIu32"\n", stream);
          return AVERROR(EAGAIN);
      }
  
      if (stream == 1 && s->nb_streams < 2) {
          av_log(s, AV_LOG_ERROR, "got audio packet without having an audio stream\n");
          return AVERROR_INVALIDDATA;
      }
  
      if ((ret2 = av_new_packet(pkt, ret)) < 0)
          return ret2;
  
      if ((ret2 = avio_read(pb, pkt->data, ret)) != ret) {
          av_free_packet(pkt);
          return ret2 < 0 ? ret2 : AVERROR_EOF;
      }
  
      pkt->stream_index = stream;
  
      if (!stream) {
          //picture type (0 = closed I, 1 = open I, 2 = P, 3 = B)
          if (((lxf->video_format >> 22) & 0x3) < 2)
              pkt->flags |= AV_PKT_FLAG_KEY;
  
          pkt->dts = lxf->frame_number++;
      }
  
      return ret;
  }
  
  AVInputFormat ff_lxf_demuxer = {
      .name           = "lxf",
      .long_name      = NULL_IF_CONFIG_SMALL("VR native stream (LXF)"),
      .priv_data_size = sizeof(LXFDemuxContext),
      .read_probe     = lxf_probe,
      .read_header    = lxf_read_header,
      .read_packet    = lxf_read_packet,
      .codec_tag      = (const AVCodecTag* const []){lxf_tags, 0},
  };
  