text: /*
   * General DV muxer/demuxer
   * Copyright (c) 2003 Roman Shaposhnik
   *
   * Many thanks to Dan Dennedy <dan@dennedy.org> for providing wealth
   * of DV technical info.
   *
   * Raw DV format
   * Copyright (c) 2002 Fabrice Bellard
   *
   * 50 Mbps (DVCPRO50) support
   * Copyright (c) 2006 Daniel Maas <dmaas@maasdigital.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 <time.h>
  
  #include "libavutil/time_internal.h"
  #include "avformat.h"
  #include "internal.h"
  #include "libavcodec/dv_profile.h"
  #include "libavcodec/dv.h"
  #include "dv.h"
  #include "libavutil/avassert.h"
  #include "libavutil/fifo.h"
  #include "libavutil/mathematics.h"
  #include "libavutil/intreadwrite.h"
  #include "libavutil/opt.h"
  #include "libavutil/timecode.h"
  
  #define MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32-bit audio
  
  struct DVMuxContext {
      AVClass          *av_class;
      const AVDVProfile*  sys;           /* current DV profile, e.g.: 525/60, 625/50 */
      int               n_ast;         /* number of stereo audio streams (up to 2) */
      AVStream         *ast[4];        /* stereo audio streams */
      AVFifoBuffer     *audio_data[4]; /* FIFO for storing excessive amounts of PCM */
      int               frames;        /* current frame number */
      int64_t           start_time;    /* recording start time */
      int               has_audio;     /* frame under construction has audio */
      int               has_video;     /* frame under construction has video */
      uint8_t           frame_buf[DV_MAX_FRAME_SIZE]; /* frame under construction */
      AVTimecode        tc;            /* timecode context */
  };
  
  static const int dv_aaux_packs_dist[12][9] = {
      { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
      { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
      { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
      { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
      { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
      { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
      { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
      { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
      { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
      { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
      { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
      { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
  };
  
  static void brktimegm(time_t secs, struct tm *tm)
  {
      tm = gmtime_r(&secs, tm);
  
      tm->tm_year += 1900; /* unlike gmtime_r we store complete year here */
      tm->tm_mon  += 1;    /* unlike gmtime_r tm_mon is from 1 to 12 */
  }
  
  static int dv_audio_frame_size(const AVDVProfile* sys, int frame, int sample_rate)
  {
      if ((sys->time_base.den == 25 || sys->time_base.den == 50) && sys->time_base.num == 1) {
          if      (sample_rate == 32000) return 1280;
          else if (sample_rate == 44100) return 1764;
          else                           return 1920;
      }
  
      av_assert0(sample_rate == 48000);
  
      return sys->audio_samples_dist[frame % (sizeof(sys->audio_samples_dist) /
                                              sizeof(sys->audio_samples_dist[0]))];
  }
  
  static int dv_write_pack(enum dv_pack_type pack_id, DVMuxContext *c, uint8_t* buf, int channel, int seq)
  {
      struct tm tc;
      time_t ct;
      uint32_t timecode;
      int audio_type = 0;
  
      buf[0] = (uint8_t)pack_id;
      switch (pack_id) {
      case dv_timecode:
          timecode  = av_timecode_get_smpte_from_framenum(&c->tc, c->frames);
          timecode |= 1<<23 | 1<<15 | 1<<7 | 1<<6; // biphase and binary group flags
          AV_WB32(buf + 1, timecode);
          break;
      case dv_audio_source:  /* AAUX source pack */
          if (c->ast[channel]->codecpar->sample_rate == 44100) {
              audio_type = 1;
          } else if (c->ast[channel]->codecpar->sample_rate == 32000)
              audio_type = 2;
          buf[1] = (1 << 7) | /* locked mode -- SMPTE only supports locked mode */
                   (1 << 6) | /* reserved -- always 1 */
                   (dv_audio_frame_size(c->sys, c->frames, c->ast[channel]->codecpar->sample_rate) -
                    c->sys->audio_min_samples[audio_type]);
                              /* # of samples      */
          buf[2] = (0 << 7) | /* multi-stereo      */
                   (0 << 5) | /* #of audio channels per block: 0 -- 1 channel */
                   (0 << 4) | /* pair bit: 0 -- one pair of channels */
                   (seq >= c->sys->difseg_size/2); /* audio mode (1st or 2nd channel) */
          buf[3] = (1 << 7) | /* res               */
                   (1 << 6) | /* multi-language flag */
                   (c->sys->dsf << 5) | /*  system: 60fields/50fields */
                   (DV_PROFILE_IS_HD(c->sys) ? 0x3 : c->sys->video_stype ? 2 : 0); /* stype */
          buf[4] = (1 << 7) | /* emphasis: 1 -- off */
                   (0 << 6) | /* emphasis time constant: 0 -- reserved */
                   (audio_type << 3) | /* frequency: 0 -- 48kHz, 1 -- 44,1kHz, 2 -- 32kHz */
                    0;        /* quantization: 0 -- 16-bit linear, 1 -- 12-bit nonlinear */
  
          break;
      case dv_audio_control:
          buf[1] = (0 << 6) | /* copy protection: 0 -- unrestricted */
                   (1 << 4) | /* input source: 1 -- digital input */
                   (3 << 2) | /* compression: 3 -- no information */
                    0;        /* misc. info/SMPTE emphasis off */
          buf[2] = (1 << 7) | /* recording start point: 1 -- no */
                   (1 << 6) | /* recording end point: 1 -- no */
                   (1 << 3) | /* recording mode: 1 -- original */
                    7;
          buf[3] = (1 << 7) | /* direction: 1 -- forward */
                   (c->sys->pix_fmt == AV_PIX_FMT_YUV420P ? 0x20 : /* speed */
                                                         c->sys->ltc_divisor * 4);
          buf[4] = (1 << 7) | /* reserved -- always 1 */
                    0x7f;     /* genre category */
          break;
      case dv_audio_recdate:
      case dv_video_recdate:  /* VAUX recording date */
          ct = c->start_time + av_rescale_rnd(c->frames, c->sys->time_base.num,
                                              c->sys->time_base.den, AV_ROUND_DOWN);
          brktimegm(ct, &tc);
          buf[1] = 0xff; /* ds, tm, tens of time zone, units of time zone */
                         /* 0xff is very likely to be "unknown" */
          buf[2] = (3 << 6) | /* reserved -- always 1 */
                   ((tc.tm_mday / 10) << 4) | /* Tens of day */
                   (tc.tm_mday % 10);         /* Units of day */
          buf[3] = /* we set high 4 bits to 0, shouldn't we set them to week? */
                   ((tc.tm_mon / 10) << 4) |    /* Tens of month */
                   (tc.tm_mon  % 10);           /* Units of month */
          buf[4] = (((tc.tm_year % 100) / 10) << 4) | /* Tens of year */
                   (tc.tm_year % 10);                 /* Units of year */
          break;
      case dv_audio_rectime:  /* AAUX recording time */
      case dv_video_rectime:  /* VAUX recording time */
          ct = c->start_time + av_rescale_rnd(c->frames, c->sys->time_base.num,
                                                         c->sys->time_base.den, AV_ROUND_DOWN);
          brktimegm(ct, &tc);
          buf[1] = (3 << 6) | /* reserved -- always 1 */
                   0x3f; /* tens of frame, units of frame: 0x3f - "unknown" ? */
          buf[2] = (1 << 7) | /* reserved -- always 1 */
                   ((tc.tm_sec / 10) << 4) | /* Tens of seconds */
                   (tc.tm_sec % 10);         /* Units of seconds */
          buf[3] = (1 << 7) | /* reserved -- always 1 */
                   ((tc.tm_min / 10) << 4) | /* Tens of minutes */
                   (tc.tm_min % 10);         /* Units of minutes */
          buf[4] = (3 << 6) | /* reserved -- always 1 */
                   ((tc.tm_hour / 10) << 4) | /* Tens of hours */
                   (tc.tm_hour % 10);         /* Units of hours */
          break;
      default:
          buf[1] = buf[2] = buf[3] = buf[4] = 0xff;
      }
      return 5;
  }
  
  static void dv_inject_audio(DVMuxContext *c, int channel, uint8_t* frame_ptr)
  {
      int i, j, d, of, size;
      size = 4 * dv_audio_frame_size(c->sys, c->frames, c->ast[channel]->codecpar->sample_rate);
      frame_ptr += channel * c->sys->difseg_size * 150 * 80;
      for (i = 0; i < c->sys->difseg_size; i++) {
          frame_ptr += 6 * 80; /* skip DIF segment header */
          for (j = 0; j < 9; j++) {
              dv_write_pack(dv_aaux_packs_dist[i][j], c, &frame_ptr[3], channel, i);
              for (d = 8; d < 80; d+=2) {
                  of = c->sys->audio_shuffle[i][j] + (d - 8)/2 * c->sys->audio_stride;
                  if (of*2 >= size)
                      continue;
  
                  // FIXME: maybe we have to admit that DV is a big-endian PCM
                  av_fifo_generic_peek_at(c->audio_data[channel], frame_ptr + d, of * 2, 2, NULL);
                  FFSWAP(uint8_t, frame_ptr[d], frame_ptr[d + 1]);
              }
              frame_ptr += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
          }
      }
  }
  
  static void dv_inject_metadata(DVMuxContext *c, uint8_t* frame)
  {
      int j, k;
      uint8_t* buf;
      int seq = 0;
  
      for (buf = frame; buf < frame + c->sys->frame_size; buf += 150 * 80, seq++) {
          /* DV subcode: 2nd and 3d DIFs */
          for (j = 80; j < 80 * 3; j += 80) {
              for (k = 6; k < 6 * 8; k += 8)
                  dv_write_pack(dv_timecode, c, &buf[j+k], 0, seq);
  
              if (((long)(buf-frame)/(c->sys->frame_size/(c->sys->difseg_size*c->sys->n_difchan))%c->sys->difseg_size) > 5) { /* FIXME: is this really needed ? */
                  dv_write_pack(dv_video_recdate, c, &buf[j+14], 0, seq);
                  dv_write_pack(dv_video_rectime, c, &buf[j+22], 0, seq);
                  dv_write_pack(dv_video_recdate, c, &buf[j+38], 0, seq);
                  dv_write_pack(dv_video_rectime, c, &buf[j+46], 0, seq);
              }
          }
  
          /* DV VAUX: 4th, 5th and 6th 3DIFs */
          for (j = 80*3 + 3; j < 80*6; j += 80) {
              dv_write_pack(dv_video_recdate, c, &buf[j+5* 2], 0, seq);
              dv_write_pack(dv_video_rectime, c, &buf[j+5* 3], 0, seq);
              dv_write_pack(dv_video_recdate, c, &buf[j+5*11], 0, seq);
              dv_write_pack(dv_video_rectime, c, &buf[j+5*12], 0, seq);
          }
      }
  }
  
  /*
   * The following 3 functions constitute our interface to the world
   */
  
  static int dv_assemble_frame(AVFormatContext *s,
                               DVMuxContext *c, AVStream* st,
                               uint8_t* data, int data_size, uint8_t** frame)
  {
      int i, reqasize;
  
      *frame = &c->frame_buf[0];
  
      switch (st->codecpar->codec_type) {
      case AVMEDIA_TYPE_VIDEO:
          /* FIXME: we have to have more sensible approach than this one */
          if (c->has_video)
              av_log(s, AV_LOG_ERROR, "Can't process DV frame #%d. Insufficient audio data or severe sync problem.\n", c->frames);
          if (data_size != c->sys->frame_size) {
              av_log(s, AV_LOG_ERROR, "Unexpected frame size, %d != %d\n",
                     data_size, c->sys->frame_size);
              return AVERROR(ENOSYS);
          }
  
          memcpy(*frame, data, c->sys->frame_size);
          c->has_video = 1;
          break;
      case AVMEDIA_TYPE_AUDIO:
          for (i = 0; i < c->n_ast && st != c->ast[i]; i++);
  
            /* FIXME: we have to have more sensible approach than this one */
          if (av_fifo_size(c->audio_data[i]) + data_size >= 100*MAX_AUDIO_FRAME_SIZE)
              av_log(s, AV_LOG_ERROR, "Can't process DV frame #%d. Insufficient video data or severe sync problem.\n", c->frames);
          av_fifo_generic_write(c->audio_data[i], data, data_size, NULL);
  
          reqasize = 4 * dv_audio_frame_size(c->sys, c->frames, st->codecpar->sample_rate);
  
          /* Let us see if we've got enough audio for one DV frame. */
          c->has_audio |= ((reqasize <= av_fifo_size(c->audio_data[i])) << i);
  
          break;
      default:
          break;
      }
  
      /* Let us see if we have enough data to construct one DV frame. */
      if (c->has_video == 1 && c->has_audio + 1 == 1 << c->n_ast) {
          dv_inject_metadata(c, *frame);
          c->has_audio = 0;
          for (i=0; i < c->n_ast; i++) {
              dv_inject_audio(c, i, *frame);
              reqasize = 4 * dv_audio_frame_size(c->sys, c->frames, c->ast[i]->codecpar->sample_rate);
              av_fifo_drain(c->audio_data[i], reqasize);
              c->has_audio |= ((reqasize <= av_fifo_size(c->audio_data[i])) << i);
          }
  
          c->has_video = 0;
  
          c->frames++;
  
          return c->sys->frame_size;
      }
  
      return 0;
  }
  
  static DVMuxContext* dv_init_mux(AVFormatContext* s)
  {
      DVMuxContext *c = s->priv_data;
      AVStream *vst = NULL;
      int i;
  
      /* we support at most 1 video and 2 audio streams */
      if (s->nb_streams > 5)
          return NULL;
  
      /* We have to sort out where audio and where video stream is */
      for (i=0; i<s->nb_streams; i++) {
          AVStream *st = s->streams[i];
          switch (st->codecpar->codec_type) {
          case AVMEDIA_TYPE_VIDEO:
              if (vst) return NULL;
              if (st->codecpar->codec_id != AV_CODEC_ID_DVVIDEO)
                  goto bail_out;
              vst = st;
              break;
          case AVMEDIA_TYPE_AUDIO:
              if (c->n_ast > 1) return NULL;
              /* Some checks -- DV format is very picky about its incoming streams */
              if(st->codecpar->codec_id    != AV_CODEC_ID_PCM_S16LE ||
                 st->codecpar->channels    != 2)
                  goto bail_out;
              if (st->codecpar->sample_rate != 48000 &&
                  st->codecpar->sample_rate != 44100 &&
                  st->codecpar->sample_rate != 32000    )
                  goto bail_out;
              c->ast[c->n_ast++] = st;
              break;
          default:
              goto bail_out;
          }
      }
  
      if (!vst)
          goto bail_out;
  
      c->sys = av_dv_codec_profile2(vst->codecpar->width, vst->codecpar->height,
                                    vst->codecpar->format, vst->time_base);
      if (!c->sys)
          goto bail_out;
  
      if ((c->sys->time_base.den != 25 && c->sys->time_base.den != 50) || c->sys->time_base.num != 1) {
          if (c->ast[0] && c->ast[0]->codecpar->sample_rate != 48000)
              goto bail_out;
          if (c->ast[1] && c->ast[1]->codecpar->sample_rate != 48000)
              goto bail_out;
      }
  
      if (((c->n_ast > 1) && (c->sys->n_difchan < 2)) ||
          ((c->n_ast > 2) && (c->sys->n_difchan < 4))) {
          /* only 2 stereo pairs allowed in 50Mbps mode */
          goto bail_out;
      }
  
      /* Ok, everything seems to be in working order */
      c->frames     = 0;
      c->has_audio  = 0;
      c->has_video  = 0;
      ff_parse_creation_time_metadata(s, &c->start_time, 1);
  
      for (i=0; i < c->n_ast; i++) {
          if (c->ast[i] && !(c->audio_data[i]=av_fifo_alloc_array(100, MAX_AUDIO_FRAME_SIZE))) {
              goto bail_out;
          }
      }
  
      return c;
  
  bail_out:
      return NULL;
  }
  
  static int dv_write_header(AVFormatContext *s)
  {
      AVRational rate;
      DVMuxContext *dvc = s->priv_data;
      AVDictionaryEntry *tcr = av_dict_get(s->metadata, "timecode", NULL, 0);
  
      if (!dv_init_mux(s)) {
          av_log(s, AV_LOG_ERROR, "Can't initialize DV format!\n"
                      "Make sure that you supply exactly two streams:\n"
                      "     video: 25fps or 29.97fps, audio: 2ch/48|44|32kHz/PCM\n"
                      "     (50Mbps allows an optional second audio stream)\n");
          return -1;
      }
      rate.num = dvc->sys->ltc_divisor;
      rate.den = 1;
      if (!tcr) { // no global timecode, look into the streams
          int i;
          for (i = 0; i < s->nb_streams; i++) {
              tcr = av_dict_get(s->streams[i]->metadata, "timecode", NULL, 0);
              if (tcr)
                  break;
          }
      }
      if (tcr && av_timecode_init_from_string(&dvc->tc, rate, tcr->value, s) >= 0)
          return 0;
      return av_timecode_init(&dvc->tc, rate, 0, 0, s);
  }
  
  static int dv_write_packet(struct AVFormatContext *s, AVPacket *pkt)
  {
      uint8_t* frame;
      int fsize;
  
      fsize = dv_assemble_frame(s, s->priv_data, s->streams[pkt->stream_index],
                                pkt->data, pkt->size, &frame);
      if (fsize < 0) {
          return fsize;
      }
      avio_write(s->pb, frame, fsize);
      return 0;
  }
  
  /*
   * We might end up with some extra A/V data without matching counterpart.
   * E.g. video data without enough audio to write the complete frame.
   * Currently we simply drop the last frame. I don't know whether this
   * is the best strategy of all
   */
  static void dv_deinit(AVFormatContext *s)
  {
      DVMuxContext *c = s->priv_data;
  
      for (int i = 0; i < c->n_ast; i++)
          av_fifo_freep(&c->audio_data[i]);
  }
  
  const AVOutputFormat ff_dv_muxer = {
      .name              = "dv",
      .long_name         = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),
      .extensions        = "dv",
      .priv_data_size    = sizeof(DVMuxContext),
      .audio_codec       = AV_CODEC_ID_PCM_S16LE,
      .video_codec       = AV_CODEC_ID_DVVIDEO,
      .write_header      = dv_write_header,
      .write_packet      = dv_write_packet,
      .deinit            = dv_deinit,
  };
  