/*

  * General DV 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) and 100 Mbps (DVCPRO HD) support

  * Copyright (c) 2006 Daniel Maas <dmaas@maasdigital.com>

  * Funded by BBC Research & Development

  *

  * 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 "avformat.h"

 #include "internal.h"

 #include "libavcodec/dv_profile.h"

 #include "libavcodec/dv.h"

 #include "libavutil/channel_layout.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/mathematics.h"

 #include "libavutil/timecode.h"

 #include "dv.h"

 #include "libavutil/avassert.h"

 
 struct DVDemuxContext {

     const AVDVProfile*  sys;    /* Current DV profile. E.g.: 525/60, 625/50 */

     AVFormatContext*  fctx;
     AVStream*         vst;
     AVStream*         ast[4];
     AVPacket          audio_pkt[4];
     uint8_t           audio_buf[4][8192];
     int               ach;
     int               frames;
     uint64_t          abytes;

 };

 static inline uint16_t dv_audio_12to16(uint16_t sample)
 {
     uint16_t shift, result;

     sample = (sample < 0x800) ? sample : sample | 0xf000;

     shift  = (sample & 0xf00) >> 8;

 
     if (shift < 0x2 || shift > 0xd) {

         result = sample;

     } else if (shift < 0x8) {
         shift--;

         result = (sample - (256 * shift)) << shift;

     } else {

         shift  = 0xe - shift;

         result = ((sample + ((256 * shift) + 1)) << shift) - 1;

     }
 
     return result;
 }
 

 static const uint8_t *dv_extract_pack(const uint8_t *frame, enum dv_pack_type t)

 {
     int offs;

     int c;

     for (c = 0; c < 10; c++) {
         switch (t) {
         case dv_audio_source:
             if (c&1)    offs = (80 * 6 + 80 * 16 * 0 + 3 + c*12000);
             else        offs = (80 * 6 + 80 * 16 * 3 + 3 + c*12000);
             break;
         case dv_audio_control:
             if (c&1)    offs = (80 * 6 + 80 * 16 * 1 + 3 + c*12000);
             else        offs = (80 * 6 + 80 * 16 * 4 + 3 + c*12000);
             break;
         case dv_video_control:
             if (c&1)    offs = (80 * 3 + 8      + c*12000);
             else        offs = (80 * 5 + 48 + 5 + c*12000);
             break;
         case dv_timecode:
             offs = (80*1 + 3 + 3);
             break;
         default:
             return NULL;
         }
         if (frame[offs] == t)
             break;

     }

     return frame[offs] == t ? &frame[offs] : NULL;

 }
 

 static const int dv_audio_frequency[3] = {
     48000, 44100, 32000,
 };
 

 /*

  * There's a couple of assumptions being made here:

  * 1. By default we silence erroneous (0x8000/16-bit 0x800/12-bit) audio samples.

  *    We can pass them upwards when libavcodec will be ready to deal with them.

  * 2. We don't do software emphasis.

  * 3. Audio is always returned as 16-bit linear samples: 12-bit nonlinear samples
  *    are converted into 16-bit linear ones.

  */

 static int dv_extract_audio(const uint8_t *frame, uint8_t **ppcm,

                             const AVDVProfile *sys)

 {

     int size, chan, i, j, d, of, smpls, freq, quant, half_ch;

     uint16_t lc, rc;

     const uint8_t *as_pack;

     uint8_t *pcm, ipcm;

     as_pack = dv_extract_pack(frame, dv_audio_source);
     if (!as_pack)    /* No audio ? */

         return 0;

     smpls = as_pack[1]      & 0x3f; /* samples in this frame - min. samples */
     freq  = as_pack[4] >> 3 & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */

     quant = as_pack[4]      & 0x07; /* 0 - 16-bit linear, 1 - 12-bit nonlinear */

     if (quant > 1)

         return -1;  /* unsupported quantization */

     if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency))
         return AVERROR_INVALIDDATA;
 

     size    = (sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */

     half_ch = sys->difseg_size / 2;

     /* We work with 720p frames split in half, thus even frames have

      * channels 0,1 and odd 2,3. */
     ipcm = (sys->height == 720 && !(frame[1] & 0x0C)) ? 2 : 0;

     if (ipcm + sys->n_difchan > (quant == 1 ? 2 : 4)) {
         av_log(NULL, AV_LOG_ERROR, "too many dv pcm frames\n");
         return AVERROR_INVALIDDATA;
     }
 

     /* for each DIF channel */
     for (chan = 0; chan < sys->n_difchan; chan++) {

         av_assert0(ipcm<4);
         pcm = ppcm[ipcm++];
         if (!pcm)
             break;

         /* for each DIF segment */
         for (i = 0; i < sys->difseg_size; i++) {
             frame += 6 * 80; /* skip DIF segment header */
             if (quant == 1 && i == half_ch) {

                 /* next stereo channel (12-bit mode only) */

                 av_assert0(ipcm<4);

                 pcm = ppcm[ipcm++];
                 if (!pcm)

                     break;
             }

             /* for each AV sequence */
             for (j = 0; j < 9; j++) {
                 for (d = 8; d < 80; d += 2) {

                     if (quant == 0) {  /* 16-bit quantization */

                         of = sys->audio_shuffle[i][j] +
                              (d - 8) / 2 * sys->audio_stride;
                         if (of * 2 >= size)

                             continue;
 

                         /* FIXME: maybe we have to admit that DV is a
                          * big-endian PCM */
                         pcm[of * 2]     = frame[d + 1];
                         pcm[of * 2 + 1] = frame[d];
 
                         if (pcm[of * 2 + 1] == 0x80 && pcm[of * 2] == 0x00)
                             pcm[of * 2 + 1] = 0;

                     } else {           /* 12-bit quantization */

                         lc = ((uint16_t)frame[d]     << 4) |
                              ((uint16_t)frame[d + 2] >> 4);
                         rc = ((uint16_t)frame[d + 1] << 4) |
                              ((uint16_t)frame[d + 2] & 0x0f);

                         lc = (lc == 0x800 ? 0 : dv_audio_12to16(lc));
                         rc = (rc == 0x800 ? 0 : dv_audio_12to16(rc));
 

                         of = sys->audio_shuffle[i % half_ch][j] +
                              (d - 8) / 3 * sys->audio_stride;
                         if (of * 2 >= size)

                             continue;
 

                         /* FIXME: maybe we have to admit that DV is a
                          * big-endian PCM */
                         pcm[of * 2]     = lc & 0xff;
                         pcm[of * 2 + 1] = lc >> 8;
                         of = sys->audio_shuffle[i % half_ch + half_ch][j] +
                              (d - 8) / 3 * sys->audio_stride;
                         /* FIXME: maybe we have to admit that DV is a
                          * big-endian PCM */
                         pcm[of * 2]     = rc & 0xff;
                         pcm[of * 2 + 1] = rc >> 8;

                         ++d;
                     }
                 }
 
                 frame += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
             }

         }
     }
 
     return size;
 }
 

 static int dv_extract_audio_info(DVDemuxContext *c, const uint8_t *frame)

 {

     const uint8_t *as_pack;

     int freq, stype, smpls, quant, i, ach;

 
     as_pack = dv_extract_pack(frame, dv_audio_source);

     if (!as_pack || !c->sys) {    /* No audio ? */

         c->ach = 0;

         return 0;

     }

     smpls = as_pack[1]      & 0x3f; /* samples in this frame - min. samples */
     freq  = as_pack[4] >> 3 & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
     stype = as_pack[3]      & 0x1f; /* 0 - 2CH, 2 - 4CH, 3 - 8CH */

     quant = as_pack[4]      & 0x07; /* 0 - 16-bit linear, 1 - 12-bit nonlinear */

     if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency)) {
         av_log(c->fctx, AV_LOG_ERROR,
                "Unrecognized audio sample rate index (%d)\n", freq);
         return 0;
     }
 

     if (stype > 3) {
         av_log(c->fctx, AV_LOG_ERROR, "stype %d is invalid\n", stype);
         c->ach = 0;
         return 0;
     }
 

     /* note: ach counts PAIRS of channels (i.e. stereo channels) */

     ach = ((int[4]) { 1, 0, 2, 4 })[stype];

     if (ach == 1 && quant && freq == 2)
         ach = 2;

 
     /* Dynamic handling of the audio streams in DV */

     for (i = 0; i < ach; i++) {

         if (!c->ast[i]) {
             c->ast[i] = avformat_new_stream(c->fctx, NULL);
             if (!c->ast[i])
                 break;
             avpriv_set_pts_info(c->ast[i], 64, 1, 30000);

             c->ast[i]->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
             c->ast[i]->codecpar->codec_id   = AV_CODEC_ID_PCM_S16LE;

 
             av_init_packet(&c->audio_pkt[i]);
             c->audio_pkt[i].size         = 0;
             c->audio_pkt[i].data         = c->audio_buf[i];
             c->audio_pkt[i].stream_index = c->ast[i]->index;
             c->audio_pkt[i].flags       |= AV_PKT_FLAG_KEY;
         }

         c->ast[i]->codecpar->sample_rate    = dv_audio_frequency[freq];
         c->ast[i]->codecpar->channels       = 2;
         c->ast[i]->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
         c->ast[i]->codecpar->bit_rate       = 2 * dv_audio_frequency[freq] * 16;

         c->ast[i]->start_time            = 0;

     }

     c->ach = i;

     return (c->sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */

 }
 

 static int dv_extract_video_info(DVDemuxContext *c, const uint8_t *frame)

 {

     const uint8_t *vsc_pack;

     AVCodecParameters *par;

     int apt, is16_9;

     par = c->vst->codecpar;

 
     avpriv_set_pts_info(c->vst, 64, c->sys->time_base.num,
                         c->sys->time_base.den);
     c->vst->avg_frame_rate = av_inv_q(c->vst->time_base);
 
     /* finding out SAR is a little bit messy */
     vsc_pack = dv_extract_pack(frame, dv_video_control);
     apt      = frame[4] & 0x07;
     is16_9   = (vsc_pack && ((vsc_pack[2] & 0x07) == 0x02 ||
                              (!apt && (vsc_pack[2] & 0x07) == 0x07)));
     c->vst->sample_aspect_ratio = c->sys->sar[is16_9];

     par->bit_rate = av_rescale_q(c->sys->frame_size,

                                    (AVRational) { 8, 1 },
                                    c->sys->time_base);

     return c->sys->frame_size;

 }
 

 static int dv_extract_timecode(DVDemuxContext* c, const uint8_t* frame, char *tc)

 {
     const uint8_t *tc_pack;
 
     // For PAL systems, drop frame bit is replaced by an arbitrary
     // bit so its value should not be considered. Drop frame timecode
     // is only relevant for NTSC systems.

     int prevent_df = c->sys->ltc_divisor == 25 || c->sys->ltc_divisor == 50;

     tc_pack = dv_extract_pack(frame, dv_timecode);
     if (!tc_pack)
         return 0;
     av_timecode_make_smpte_tc_string(tc, AV_RB32(tc_pack + 1), prevent_df);

     return 1;
 }
 

 /* The following 3 functions constitute our interface to the world */

 DVDemuxContext *avpriv_dv_init_demux(AVFormatContext *s)

 {
     DVDemuxContext *c;
 
     c = av_mallocz(sizeof(DVDemuxContext));
     if (!c)
         return NULL;
 

     c->vst = avformat_new_stream(s, NULL);

     if (!c->vst) {

         av_free(c);

         return NULL;
     }

     c->fctx                   = s;

     c->vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
     c->vst->codecpar->codec_id   = AV_CODEC_ID_DVVIDEO;
     c->vst->codecpar->bit_rate   = 25000000;

     c->vst->start_time        = 0;

     return c;

 }
 

 int avpriv_dv_get_packet(DVDemuxContext *c, AVPacket *pkt)

 {

     int size = -1;

     int i;
 

     for (i = 0; i < c->ach; i++) {

         if (c->ast[i] && c->audio_pkt[i].size) {

             *pkt                 = c->audio_pkt[i];

             c->audio_pkt[i].size = 0;

             size                 = pkt->size;

             break;
         }

     }

 
     return size;
 }
 

 int avpriv_dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,

                              uint8_t *buf, int buf_size, int64_t pos)

 {

     int size, i;

     uint8_t *ppcm[5] = { 0 };

     if (buf_size < DV_PROFILE_BYTES ||

         !(c->sys = av_dv_frame_profile(c->sys, buf, buf_size)) ||

         buf_size < c->sys->frame_size) {

         return -1;   /* Broken frame, or not enough data */

     }

 
     /* Queueing audio packet */
     /* FIXME: in case of no audio/bad audio we have to do something */

     size = dv_extract_audio_info(c, buf);

     for (i = 0; i < c->ach; i++) {

         c->audio_pkt[i].pos  = pos;

         c->audio_pkt[i].size = size;

         c->audio_pkt[i].pts  = c->abytes * 30000 * 8 /

                                c->ast[i]->codecpar->bit_rate;

         ppcm[i] = c->audio_buf[i];

     }

     if (c->ach)
         dv_extract_audio(buf, ppcm, c->sys);

     /* We work with 720p frames split in half, thus even frames have
      * channels 0,1 and odd 2,3. */

     if (c->sys->height == 720) {

         if (buf[1] & 0x0C) {

             c->audio_pkt[2].size = c->audio_pkt[3].size = 0;

         } else {

             c->audio_pkt[0].size = c->audio_pkt[1].size = 0;

             c->abytes           += size;

         }
     } else {
         c->abytes += size;

     }
 

     /* Now it's time to return video packet */

     size = dv_extract_video_info(c, buf);

     av_init_packet(pkt);

     pkt->data         = buf;

     pkt->pos          = pos;

     pkt->size         = size;

     pkt->flags       |= AV_PKT_FLAG_KEY;

     pkt->stream_index = c->vst->index;

     pkt->pts          = c->frames;

     c->frames++;

     return size;
 }

 static int64_t dv_frame_offset(AVFormatContext *s, DVDemuxContext *c,

                                int64_t timestamp, int flags)

 {

     // FIXME: sys may be wrong if last dv_read_packet() failed (buffer is junk)

     const int frame_size = c->sys->frame_size;

     int64_t offset;

     int64_t size       = avio_size(s->pb) - s->internal->data_offset;

     int64_t max_offset = ((size - 1) / frame_size) * frame_size;

     offset = frame_size * timestamp;

     if (size >= 0 && offset > max_offset)
         offset = max_offset;
     else if (offset < 0)
         offset = 0;

     return offset + s->internal->data_offset;

 }
 

 void ff_dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)

 {

     c->frames = frame_offset;

     if (c->ach) {
         if (c->sys) {

         c->abytes = av_rescale_q(c->frames, c->sys->time_base,

                                  (AVRational) { 8, c->ast[0]->codecpar->bit_rate });

         } else

             av_log(c->fctx, AV_LOG_ERROR, "cannot adjust audio bytes\n");
     }

     c->audio_pkt[0].size = c->audio_pkt[1].size = 0;

     c->audio_pkt[2].size = c->audio_pkt[3].size = 0;

 }
 

 /************************************************************
  * Implementation of the easiest DV storage of all -- raw DV.
  ************************************************************/

 typedef struct RawDVContext {

     DVDemuxContext *dv_demux;

     uint8_t         buf[DV_MAX_FRAME_SIZE];

 } RawDVContext;
 

 static int dv_read_timecode(AVFormatContext *s) {
     int ret;

     char timecode[AV_TIMECODE_STR_SIZE];

     int64_t pos = avio_tell(s->pb);
 
     // Read 3 DIF blocks: Header block and 2 Subcode blocks.
     int partial_frame_size = 3 * 80;
     uint8_t *partial_frame = av_mallocz(sizeof(*partial_frame) *
                                         partial_frame_size);
 
     RawDVContext *c = s->priv_data;

     if (!partial_frame)
         return AVERROR(ENOMEM);
 

     ret = avio_read(s->pb, partial_frame, partial_frame_size);
     if (ret < 0)
         goto finish;
 
     if (ret < partial_frame_size) {
         ret = -1;
         goto finish;
     }
 
     ret = dv_extract_timecode(c->dv_demux, partial_frame, timecode);
     if (ret)
         av_dict_set(&s->metadata, "timecode", timecode, 0);

     else

         av_log(s, AV_LOG_ERROR, "Detected timecode is invalid\n");

 
 finish:
     av_free(partial_frame);
     avio_seek(s->pb, pos, SEEK_SET);
     return ret;
 }
 

 static int dv_read_header(AVFormatContext *s)

 {

     unsigned state, marker_pos = 0;

     RawDVContext *c = s->priv_data;

     c->dv_demux = avpriv_dv_init_demux(s);

     if (!c->dv_demux)
         return -1;

     state = avio_rb32(s->pb);

     while ((state & 0xffffff7f) != 0x1f07003f) {

         if (avio_feof(s->pb)) {

             av_log(s, AV_LOG_ERROR, "Cannot find DV header.\n");
             return -1;
         }

         if (state == 0x003f0700 || state == 0xff3f0700)

             marker_pos = avio_tell(s->pb);
         if (state == 0xff3f0701 && avio_tell(s->pb) - marker_pos == 80) {

             avio_seek(s->pb, -163, SEEK_CUR);

             state = avio_rb32(s->pb);

             break;
         }

         state = (state << 8) | avio_r8(s->pb);

     }
     AV_WB32(c->buf, state);
 

     if (avio_read(s->pb, c->buf + 4, DV_PROFILE_BYTES - 4) != DV_PROFILE_BYTES - 4 ||

         avio_seek(s->pb, -DV_PROFILE_BYTES, SEEK_CUR) < 0)

         return AVERROR(EIO);

     c->dv_demux->sys = av_dv_frame_profile(c->dv_demux->sys,
                                            c->buf,
                                            DV_PROFILE_BYTES);

     if (!c->dv_demux->sys) {

         av_log(s, AV_LOG_ERROR,
                "Can't determine profile of DV input stream.\n");

         return -1;
     }
 

     s->bit_rate = av_rescale_q(c->dv_demux->sys->frame_size,
                                (AVRational) { 8, 1 },

                                c->dv_demux->sys->time_base);

     if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)

         dv_read_timecode(s);
 

     return 0;

 }
 
 static int dv_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     int size;

     RawDVContext *c = s->priv_data;
 

     size = avpriv_dv_get_packet(c->dv_demux, pkt);

     if (size < 0) {

         int ret;

         int64_t pos = avio_tell(s->pb);

         if (!c->dv_demux->sys)
             return AVERROR(EIO);

         size = c->dv_demux->sys->frame_size;

         ret = avio_read(s->pb, c->buf, size);
         if (ret < 0) {
             return ret;
         } else if (ret == 0) {

             return AVERROR(EIO);

         }

         size = avpriv_dv_produce_packet(c->dv_demux, pkt, c->buf, size, pos);

     }
 

     return size;

 }
 

 static int dv_read_seek(AVFormatContext *s, int stream_index,

                         int64_t timestamp, int flags)

 {

     RawDVContext *r   = s->priv_data;

     DVDemuxContext *c = r->dv_demux;

     int64_t offset    = dv_frame_offset(s, c, timestamp, flags);

     if (avio_seek(s->pb, offset, SEEK_SET) < 0)
         return -1;

     ff_dv_offset_reset(c, offset / c->sys->frame_size);

     return 0;

 }
 

 static int dv_read_close(AVFormatContext *s)

 {

     RawDVContext *c = s->priv_data;

     av_freep(&c->dv_demux);

     return 0;
 }
 

 static int dv_probe(AVProbeData *p)
 {

     unsigned marker_pos = 0;

     int i;

     int matches           = 0;

     int firstmatch        = 0;

     int secondary_matches = 0;

 
     if (p->buf_size < 5)
         return 0;
 

     for (i = 0; i < p->buf_size-4; i++) {
         unsigned state = AV_RB32(p->buf+i);
         if ((state & 0x0007f840) == 0x00070000) {
             // any section header, also with seq/chan num != 0,
             // should appear around every 12000 bytes, at least 10 per frame
             if ((state & 0xff07ff7f) == 0x1f07003f) {
                 secondary_matches++;

                 if ((state & 0xffffff7f) == 0x1f07003f) {

                     matches++;

                     if (!i)
                         firstmatch = 1;
                 }

             }
             if (state == 0x003f0700 || state == 0xff3f0700)
                 marker_pos = i;
             if (state == 0xff3f0701 && i - marker_pos == 80)
                 matches++;
         }

     }
 

     if (matches && p->buf_size / matches < 1024 * 1024) {

         if (matches > 4 || firstmatch ||

             (secondary_matches >= 10 &&
              p->buf_size / secondary_matches < 24000))
             // not max to avoid dv in mov to match
             return AVPROBE_SCORE_MAX * 3 / 4;
         return AVPROBE_SCORE_MAX / 4;

     }

     return 0;
 }
 

 AVInputFormat ff_dv_demuxer = {

     .name           = "dv",

     .long_name      = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),

     .priv_data_size = sizeof(RawDVContext),
     .read_probe     = dv_probe,
     .read_header    = dv_read_header,
     .read_packet    = dv_read_packet,
     .read_close     = dv_read_close,
     .read_seek      = dv_read_seek,

     .extensions     = "dv,dif",

 };