/*
  * 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) 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 "libavcodec/dvdata.h"

 #include "libavutil/intreadwrite.h"

 #include "dv.h"
 
 struct DVDemuxContext {

     const DVprofile*  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;
 }
 

 /*

  * This is the dumbest implementation of all -- it simply looks at
  * a fixed offset and if pack isn't there -- fails. We might want
  * to have a fallback mechanism for complete search of missing packs.
  */
 static const uint8_t* dv_extract_pack(uint8_t* frame, enum dv_pack_type t)
 {
     int offs;

     switch (t) {
     case dv_audio_source:

         offs = (80*6 + 80*16*3 + 3);
         break;

     case dv_audio_control:

         offs = (80*6 + 80*16*4 + 3);
         break;

     case dv_video_control:

         offs = (80*5 + 48 + 5);
         break;

     default:

         return NULL;

     }

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

 }
 

 /*

  * There's a couple of assumptions being made here:
  * 1. By default we silence erroneous (0x8000/16bit 0x800/12bit) audio samples.
  *    We can pass them upwards when ffmpeg will be ready to deal with them.
  * 2. We don't do software emphasis.
  * 3. Audio is always returned as 16bit linear samples: 12bit nonlinear samples
  *    are converted into 16bit linear ones.
  */

 static int dv_extract_audio(uint8_t* frame, uint8_t* ppcm[4],

                             const DVprofile *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 - 16bit linear, 1 - 12bit nonlinear */

     if (quant > 1)

         return -1; /* unsupported quantization */

 
     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;
     pcm  = ppcm[ipcm++];

     /* for each DIF channel */
     for (chan = 0; chan < sys->n_difchan; chan++) {
         /* 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 (12bit mode only) */

                 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) {  /* 16bit quantization */

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

                         if (of*2 >= size)
                             continue;
 

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

                         if (pcm[of*2+1] == 0x80 && pcm[of*2] == 0x00)
                             pcm[of*2+1] = 0;
                     } else {           /* 12bit 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;
 

                         pcm[of*2]   = lc & 0xff; // FIXME: maybe we have to admit
                         pcm[of*2+1] = lc >> 8;   //        that DV is a big-endian PCM

                         of = sys->audio_shuffle[i%half_ch+half_ch][j] +

                             (d - 8) / 3 * sys->audio_stride;

                         pcm[of*2]   = rc & 0xff; // FIXME: maybe we have to admit
                         pcm[of*2+1] = rc >> 8;   //        that DV is a big-endian PCM

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

         }

         /* next stereo channel (50Mbps and 100Mbps only) */
         pcm = ppcm[ipcm++];
         if (!pcm)

             break;

     }
 
     return size;
 }
 

 static int dv_extract_audio_info(DVDemuxContext* c, 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 - 16bit linear, 1 - 12bit nonlinear */

 
     /* 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] = av_new_stream(c->fctx, 0);

            if (!c->ast[i])
                break;
            av_set_pts_info(c->ast[i], 64, 1, 30000);

            c->ast[i]->codec->codec_type = AVMEDIA_TYPE_AUDIO;

            c->ast[i]->codec->codec_id   = 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]->codec->sample_rate = dv_audio_frequency[freq];

        c->ast[i]->codec->channels    = 2;
        c->ast[i]->codec->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, uint8_t* frame)

 {
     const uint8_t* vsc_pack;

     AVCodecContext* avctx;
     int apt, is16_9;

     int size = 0;

     if (c->sys) {

         avctx = c->vst->codec;

         av_set_pts_info(c->vst, 64, c->sys->time_base.num,
                         c->sys->time_base.den);

         avctx->time_base= c->sys->time_base;

         if (!avctx->width){

             avctx->width = c->sys->width;
             avctx->height = c->sys->height;

         }

         avctx->pix_fmt = c->sys->pix_fmt;

         /* 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];

         avctx->bit_rate = av_rescale_q(c->sys->frame_size, (AVRational){8,1},
                                        c->sys->time_base);

         size = c->sys->frame_size;

     }
     return size;
 }
 

 /*

  * The following 3 functions constitute our interface to the world

  */
 

 DVDemuxContext* dv_init_demux(AVFormatContext *s)

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

     c->vst = av_new_stream(s, 0);

     if (!c->vst) {

         av_free(c);

         return NULL;
     }

     c->sys  = NULL;

     c->fctx = s;

     memset(c->ast, 0, sizeof(c->ast));

     c->ach    = 0;

     c->frames = 0;
     c->abytes = 0;

     c->vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;

     c->vst->codec->codec_id   = CODEC_ID_DVVIDEO;
     c->vst->codec->bit_rate   = 25000000;
     c->vst->start_time        = 0;

     return c;

 }
 

 int 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 dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,

                       uint8_t* buf, int buf_size, int64_t pos)

 {

     int size, i;

     uint8_t *ppcm[4] = {0};

     if (buf_size < DV_PROFILE_BYTES ||

         !(c->sys = ff_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]->codec->bit_rate;

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

     }

     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->id;

     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 DVprofile* sys = ff_dv_codec_profile(c->vst->codec);

     int64_t offset;

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

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

     offset = sys->frame_size * timestamp;

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

     else if (offset < 0) offset = 0;

     return offset + s->data_offset;

 }
 

 void dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)

 {

     c->frames= frame_offset;
     if (c->ach)

         c->abytes= av_rescale_q(c->frames, c->sys->time_base,
                                 (AVRational){8, c->ast[0]->codec->bit_rate});

     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_header(AVFormatContext *s,
                           AVFormatParameters *ap)
 {

     unsigned state, marker_pos = 0;

     RawDVContext *c = s->priv_data;

     c->dv_demux = dv_init_demux(s);

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

     state = avio_rb32(s->pb);

     while ((state & 0xffffff7f) != 0x1f07003f) {
         if (url_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) <= 0 ||

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

         return AVERROR(EIO);

     c->dv_demux->sys = ff_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);

     return 0;

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

     RawDVContext *c = s->priv_data;
 

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

     if (size < 0) {

         int64_t pos = avio_tell(s->pb);

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

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

         if (avio_read(s->pb, c->buf, size) <= 0)

             return AVERROR(EIO);

         size = 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);

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

     offset = avio_seek(s->pb, offset, SEEK_SET);

     return (offset < 0) ? offset : 0;

 }
 

 static int dv_read_close(AVFormatContext *s)

 {

     RawDVContext *c = s->priv_data;
     av_free(c->dv_demux);

     return 0;
 }
 

 static int dv_probe(AVProbeData *p)
 {

     unsigned state, marker_pos = 0;

     int i;

     int matches = 0;

     int secondary_matches = 0;

 
     if (p->buf_size < 5)
         return 0;
 
     state = AV_RB32(p->buf);
     for (i = 4; i < p->buf_size; i++) {
         if ((state & 0xffffff7f) == 0x1f07003f)

             matches++;

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

             matches++;

         state = (state << 8) | p->buf[i];
     }
 

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

         if (matches > 4 || (secondary_matches >= 10 && p->buf_size / secondary_matches < 24000))

             return AVPROBE_SCORE_MAX*3/4; // not max to avoid dv in mov to match
         return AVPROBE_SCORE_MAX/4;
     }

     return 0;
 }
 

 #if CONFIG_DV_DEMUXER

 AVInputFormat ff_dv_demuxer = {

     "dv",

     NULL_IF_CONFIG_SMALL("DV video format"),

     sizeof(RawDVContext),

     dv_probe,

     dv_read_header,
     dv_read_packet,
     dv_read_close,

     dv_read_seek,

     .extensions = "dv,dif",

 };

 #endif