LCOV - code coverage report
Current view: top level - src/libavformat - dv.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 248 335 74.0 %
Date: 2017-06-24 07:01:58 Functions: 16 17 94.1 %

          Line data    Source code
       1             : /*
       2             :  * General DV demuxer
       3             :  * Copyright (c) 2003 Roman Shaposhnik
       4             :  *
       5             :  * Many thanks to Dan Dennedy <dan@dennedy.org> for providing wealth
       6             :  * of DV technical info.
       7             :  *
       8             :  * Raw DV format
       9             :  * Copyright (c) 2002 Fabrice Bellard
      10             :  *
      11             :  * 50 Mbps (DVCPRO50) and 100 Mbps (DVCPRO HD) support
      12             :  * Copyright (c) 2006 Daniel Maas <dmaas@maasdigital.com>
      13             :  * Funded by BBC Research & Development
      14             :  *
      15             :  * This file is part of FFmpeg.
      16             :  *
      17             :  * FFmpeg is free software; you can redistribute it and/or
      18             :  * modify it under the terms of the GNU Lesser General Public
      19             :  * License as published by the Free Software Foundation; either
      20             :  * version 2.1 of the License, or (at your option) any later version.
      21             :  *
      22             :  * FFmpeg is distributed in the hope that it will be useful,
      23             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      24             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      25             :  * Lesser General Public License for more details.
      26             :  *
      27             :  * You should have received a copy of the GNU Lesser General Public
      28             :  * License along with FFmpeg; if not, write to the Free Software
      29             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      30             :  */
      31             : #include <time.h>
      32             : #include "avformat.h"
      33             : #include "internal.h"
      34             : #include "libavcodec/dv_profile.h"
      35             : #include "libavcodec/dv.h"
      36             : #include "libavutil/channel_layout.h"
      37             : #include "libavutil/intreadwrite.h"
      38             : #include "libavutil/mathematics.h"
      39             : #include "libavutil/timecode.h"
      40             : #include "dv.h"
      41             : #include "libavutil/avassert.h"
      42             : 
      43             : struct DVDemuxContext {
      44             :     const AVDVProfile*  sys;    /* Current DV profile. E.g.: 525/60, 625/50 */
      45             :     AVFormatContext*  fctx;
      46             :     AVStream*         vst;
      47             :     AVStream*         ast[4];
      48             :     AVPacket          audio_pkt[4];
      49             :     uint8_t           audio_buf[4][8192];
      50             :     int               ach;
      51             :     int               frames;
      52             :     uint64_t          abytes;
      53             : };
      54             : 
      55           0 : static inline uint16_t dv_audio_12to16(uint16_t sample)
      56             : {
      57             :     uint16_t shift, result;
      58             : 
      59           0 :     sample = (sample < 0x800) ? sample : sample | 0xf000;
      60           0 :     shift  = (sample & 0xf00) >> 8;
      61             : 
      62           0 :     if (shift < 0x2 || shift > 0xd) {
      63           0 :         result = sample;
      64           0 :     } else if (shift < 0x8) {
      65           0 :         shift--;
      66           0 :         result = (sample - (256 * shift)) << shift;
      67             :     } else {
      68           0 :         shift  = 0xe - shift;
      69           0 :         result = ((sample + ((256 * shift) + 1)) << shift) - 1;
      70             :     }
      71             : 
      72           0 :     return result;
      73             : }
      74             : 
      75        1400 : static const uint8_t *dv_extract_pack(const uint8_t *frame, enum dv_pack_type t)
      76             : {
      77             :     int offs;
      78             :     int c;
      79             : 
      80        6710 :     for (c = 0; c < 10; c++) {
      81        6179 :         switch (t) {
      82        5524 :         case dv_audio_source:
      83        5524 :             if (c&1)    offs = (80 * 6 + 80 * 16 * 0 + 3 + c*12000);
      84        2869 :             else        offs = (80 * 6 + 80 * 16 * 3 + 3 + c*12000);
      85        5524 :             break;
      86           0 :         case dv_audio_control:
      87           0 :             if (c&1)    offs = (80 * 6 + 80 * 16 * 1 + 3 + c*12000);
      88           0 :             else        offs = (80 * 6 + 80 * 16 * 4 + 3 + c*12000);
      89           0 :             break;
      90         638 :         case dv_video_control:
      91         638 :             if (c&1)    offs = (80 * 3 + 8      + c*12000);
      92         638 :             else        offs = (80 * 5 + 48 + 5 + c*12000);
      93         638 :             break;
      94          17 :         case dv_timecode:
      95          17 :             offs = (80*1 + 3 + 3);
      96          17 :             break;
      97           0 :         default:
      98           0 :             return NULL;
      99             :         }
     100        6179 :         if (frame[offs] == t)
     101         869 :             break;
     102             :     }
     103             : 
     104        1400 :     return frame[offs] == t ? &frame[offs] : NULL;
     105             : }
     106             : 
     107             : static const int dv_audio_frequency[3] = {
     108             :     48000, 44100, 32000,
     109             : };
     110             : 
     111             : /*
     112             :  * There's a couple of assumptions being made here:
     113             :  * 1. By default we silence erroneous (0x8000/16-bit 0x800/12-bit) audio samples.
     114             :  *    We can pass them upwards when libavcodec will be ready to deal with them.
     115             :  * 2. We don't do software emphasis.
     116             :  * 3. Audio is always returned as 16-bit linear samples: 12-bit nonlinear samples
     117             :  *    are converted into 16-bit linear ones.
     118             :  */
     119         107 : static int dv_extract_audio(const uint8_t *frame, uint8_t **ppcm,
     120             :                             const AVDVProfile *sys)
     121             : {
     122             :     int size, chan, i, j, d, of, smpls, freq, quant, half_ch;
     123             :     uint16_t lc, rc;
     124             :     const uint8_t *as_pack;
     125             :     uint8_t *pcm, ipcm;
     126             : 
     127         107 :     as_pack = dv_extract_pack(frame, dv_audio_source);
     128         107 :     if (!as_pack)    /* No audio ? */
     129           0 :         return 0;
     130             : 
     131         107 :     smpls = as_pack[1]      & 0x3f; /* samples in this frame - min. samples */
     132         107 :     freq  = as_pack[4] >> 3 & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
     133         107 :     quant = as_pack[4]      & 0x07; /* 0 - 16-bit linear, 1 - 12-bit nonlinear */
     134             : 
     135         107 :     if (quant > 1)
     136           0 :         return -1;  /* unsupported quantization */
     137             : 
     138         107 :     if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency))
     139           0 :         return AVERROR_INVALIDDATA;
     140             : 
     141         107 :     size    = (sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
     142         107 :     half_ch = sys->difseg_size / 2;
     143             : 
     144             :     /* We work with 720p frames split in half, thus even frames have
     145             :      * channels 0,1 and odd 2,3. */
     146         107 :     ipcm = (sys->height == 720 && !(frame[1] & 0x0C)) ? 2 : 0;
     147             : 
     148         107 :     if (ipcm + sys->n_difchan > (quant == 1 ? 2 : 4)) {
     149           0 :         av_log(NULL, AV_LOG_ERROR, "too many dv pcm frames\n");
     150           0 :         return AVERROR_INVALIDDATA;
     151             :     }
     152             : 
     153             :     /* for each DIF channel */
     154         214 :     for (chan = 0; chan < sys->n_difchan; chan++) {
     155         107 :         av_assert0(ipcm<4);
     156         107 :         pcm = ppcm[ipcm++];
     157         107 :         if (!pcm)
     158           0 :             break;
     159             : 
     160             :         /* for each DIF segment */
     161        1331 :         for (i = 0; i < sys->difseg_size; i++) {
     162        1224 :             frame += 6 * 80; /* skip DIF segment header */
     163        1224 :             if (quant == 1 && i == half_ch) {
     164             :                 /* next stereo channel (12-bit mode only) */
     165           0 :                 av_assert0(ipcm<4);
     166           0 :                 pcm = ppcm[ipcm++];
     167           0 :                 if (!pcm)
     168           0 :                     break;
     169             :             }
     170             : 
     171             :             /* for each AV sequence */
     172       12240 :             for (j = 0; j < 9; j++) {
     173      407592 :                 for (d = 8; d < 80; d += 2) {
     174      396576 :                     if (quant == 0) {  /* 16-bit quantization */
     175      793152 :                         of = sys->audio_shuffle[i][j] +
     176      396576 :                              (d - 8) / 2 * sys->audio_stride;
     177      396576 :                         if (of * 2 >= size)
     178        4804 :                             continue;
     179             : 
     180             :                         /* FIXME: maybe we have to admit that DV is a
     181             :                          * big-endian PCM */
     182      391772 :                         pcm[of * 2]     = frame[d + 1];
     183      391772 :                         pcm[of * 2 + 1] = frame[d];
     184             : 
     185      391772 :                         if (pcm[of * 2 + 1] == 0x80 && pcm[of * 2] == 0x00)
     186           0 :                             pcm[of * 2 + 1] = 0;
     187             :                     } else {           /* 12-bit quantization */
     188           0 :                         lc = ((uint16_t)frame[d]     << 4) |
     189           0 :                              ((uint16_t)frame[d + 2] >> 4);
     190           0 :                         rc = ((uint16_t)frame[d + 1] << 4) |
     191           0 :                              ((uint16_t)frame[d + 2] & 0x0f);
     192           0 :                         lc = (lc == 0x800 ? 0 : dv_audio_12to16(lc));
     193           0 :                         rc = (rc == 0x800 ? 0 : dv_audio_12to16(rc));
     194             : 
     195           0 :                         of = sys->audio_shuffle[i % half_ch][j] +
     196           0 :                              (d - 8) / 3 * sys->audio_stride;
     197           0 :                         if (of * 2 >= size)
     198           0 :                             continue;
     199             : 
     200             :                         /* FIXME: maybe we have to admit that DV is a
     201             :                          * big-endian PCM */
     202           0 :                         pcm[of * 2]     = lc & 0xff;
     203           0 :                         pcm[of * 2 + 1] = lc >> 8;
     204           0 :                         of = sys->audio_shuffle[i % half_ch + half_ch][j] +
     205           0 :                              (d - 8) / 3 * sys->audio_stride;
     206             :                         /* FIXME: maybe we have to admit that DV is a
     207             :                          * big-endian PCM */
     208           0 :                         pcm[of * 2]     = rc & 0xff;
     209           0 :                         pcm[of * 2 + 1] = rc >> 8;
     210           0 :                         ++d;
     211             :                     }
     212             :                 }
     213             : 
     214       11016 :                 frame += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
     215             :             }
     216             :         }
     217             :     }
     218             : 
     219         107 :     return size;
     220             : }
     221             : 
     222         638 : static int dv_extract_audio_info(DVDemuxContext *c, const uint8_t *frame)
     223             : {
     224             :     const uint8_t *as_pack;
     225             :     int freq, stype, smpls, quant, i, ach;
     226             : 
     227         638 :     as_pack = dv_extract_pack(frame, dv_audio_source);
     228         638 :     if (!as_pack || !c->sys) {    /* No audio ? */
     229         531 :         c->ach = 0;
     230         531 :         return 0;
     231             :     }
     232             : 
     233         107 :     smpls = as_pack[1]      & 0x3f; /* samples in this frame - min. samples */
     234         107 :     freq  = as_pack[4] >> 3 & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
     235         107 :     stype = as_pack[3]      & 0x1f; /* 0 - 2CH, 2 - 4CH, 3 - 8CH */
     236         107 :     quant = as_pack[4]      & 0x07; /* 0 - 16-bit linear, 1 - 12-bit nonlinear */
     237             : 
     238         107 :     if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency)) {
     239           0 :         av_log(c->fctx, AV_LOG_ERROR,
     240             :                "Unrecognized audio sample rate index (%d)\n", freq);
     241           0 :         return 0;
     242             :     }
     243             : 
     244         107 :     if (stype > 3) {
     245           0 :         av_log(c->fctx, AV_LOG_ERROR, "stype %d is invalid\n", stype);
     246           0 :         c->ach = 0;
     247           0 :         return 0;
     248             :     }
     249             : 
     250             :     /* note: ach counts PAIRS of channels (i.e. stereo channels) */
     251         107 :     ach = ((int[4]) { 1, 0, 2, 4 })[stype];
     252         107 :     if (ach == 1 && quant && freq == 2)
     253           0 :         ach = 2;
     254             : 
     255             :     /* Dynamic handling of the audio streams in DV */
     256         214 :     for (i = 0; i < ach; i++) {
     257         107 :         if (!c->ast[i]) {
     258           5 :             c->ast[i] = avformat_new_stream(c->fctx, NULL);
     259           5 :             if (!c->ast[i])
     260           0 :                 break;
     261           5 :             avpriv_set_pts_info(c->ast[i], 64, 1, 30000);
     262           5 :             c->ast[i]->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
     263           5 :             c->ast[i]->codecpar->codec_id   = AV_CODEC_ID_PCM_S16LE;
     264             : 
     265           5 :             av_init_packet(&c->audio_pkt[i]);
     266           5 :             c->audio_pkt[i].size         = 0;
     267           5 :             c->audio_pkt[i].data         = c->audio_buf[i];
     268           5 :             c->audio_pkt[i].stream_index = c->ast[i]->index;
     269           5 :             c->audio_pkt[i].flags       |= AV_PKT_FLAG_KEY;
     270             :         }
     271         107 :         c->ast[i]->codecpar->sample_rate    = dv_audio_frequency[freq];
     272         107 :         c->ast[i]->codecpar->channels       = 2;
     273         107 :         c->ast[i]->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
     274         107 :         c->ast[i]->codecpar->bit_rate       = 2 * dv_audio_frequency[freq] * 16;
     275         107 :         c->ast[i]->start_time            = 0;
     276             :     }
     277         107 :     c->ach = i;
     278             : 
     279         107 :     return (c->sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
     280             : }
     281             : 
     282         638 : static int dv_extract_video_info(DVDemuxContext *c, const uint8_t *frame)
     283             : {
     284             :     const uint8_t *vsc_pack;
     285             :     AVCodecParameters *par;
     286             :     int apt, is16_9;
     287             : 
     288         638 :     par = c->vst->codecpar;
     289             : 
     290         638 :     avpriv_set_pts_info(c->vst, 64, c->sys->time_base.num,
     291         638 :                         c->sys->time_base.den);
     292         638 :     c->vst->avg_frame_rate = av_inv_q(c->vst->time_base);
     293             : 
     294             :     /* finding out SAR is a little bit messy */
     295         638 :     vsc_pack = dv_extract_pack(frame, dv_video_control);
     296         638 :     apt      = frame[4] & 0x07;
     297         638 :     is16_9   = (vsc_pack && ((vsc_pack[2] & 0x07) == 0x02 ||
     298         255 :                              (!apt && (vsc_pack[2] & 0x07) == 0x07)));
     299         638 :     c->vst->sample_aspect_ratio = c->sys->sar[is16_9];
     300         638 :     par->bit_rate = av_rescale_q(c->sys->frame_size,
     301         638 :                                    (AVRational) { 8, 1 },
     302         638 :                                    c->sys->time_base);
     303         638 :     return c->sys->frame_size;
     304             : }
     305             : 
     306          17 : static int dv_extract_timecode(DVDemuxContext* c, const uint8_t* frame, char *tc)
     307             : {
     308             :     const uint8_t *tc_pack;
     309             : 
     310             :     // For PAL systems, drop frame bit is replaced by an arbitrary
     311             :     // bit so its value should not be considered. Drop frame timecode
     312             :     // is only relevant for NTSC systems.
     313          17 :     int prevent_df = c->sys->ltc_divisor == 25 || c->sys->ltc_divisor == 50;
     314             : 
     315          17 :     tc_pack = dv_extract_pack(frame, dv_timecode);
     316          17 :     if (!tc_pack)
     317           0 :         return 0;
     318          17 :     av_timecode_make_smpte_tc_string(tc, AV_RB32(tc_pack + 1), prevent_df);
     319          17 :     return 1;
     320             : }
     321             : 
     322             : /* The following 3 functions constitute our interface to the world */
     323             : 
     324          17 : DVDemuxContext *avpriv_dv_init_demux(AVFormatContext *s)
     325             : {
     326             :     DVDemuxContext *c;
     327             : 
     328          17 :     c = av_mallocz(sizeof(DVDemuxContext));
     329          17 :     if (!c)
     330           0 :         return NULL;
     331             : 
     332          17 :     c->vst = avformat_new_stream(s, NULL);
     333          17 :     if (!c->vst) {
     334           0 :         av_free(c);
     335           0 :         return NULL;
     336             :     }
     337             : 
     338          17 :     c->fctx                   = s;
     339          17 :     c->vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
     340          17 :     c->vst->codecpar->codec_id   = AV_CODEC_ID_DVVIDEO;
     341          17 :     c->vst->codecpar->bit_rate   = 25000000;
     342          17 :     c->vst->start_time        = 0;
     343             : 
     344          17 :     return c;
     345             : }
     346             : 
     347         731 : int avpriv_dv_get_packet(DVDemuxContext *c, AVPacket *pkt)
     348             : {
     349         731 :     int size = -1;
     350             :     int i;
     351             : 
     352         836 :     for (i = 0; i < c->ach; i++) {
     353         186 :         if (c->ast[i] && c->audio_pkt[i].size) {
     354          81 :             *pkt                 = c->audio_pkt[i];
     355          81 :             c->audio_pkt[i].size = 0;
     356          81 :             size                 = pkt->size;
     357          81 :             break;
     358             :         }
     359             :     }
     360             : 
     361         731 :     return size;
     362             : }
     363             : 
     364         638 : int avpriv_dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,
     365             :                              uint8_t *buf, int buf_size, int64_t pos)
     366             : {
     367             :     int size, i;
     368         638 :     uint8_t *ppcm[5] = { 0 };
     369             : 
     370        1276 :     if (buf_size < DV_PROFILE_BYTES ||
     371        1276 :         !(c->sys = av_dv_frame_profile(c->sys, buf, buf_size)) ||
     372         638 :         buf_size < c->sys->frame_size) {
     373           0 :         return -1;   /* Broken frame, or not enough data */
     374             :     }
     375             : 
     376             :     /* Queueing audio packet */
     377             :     /* FIXME: in case of no audio/bad audio we have to do something */
     378         638 :     size = dv_extract_audio_info(c, buf);
     379         745 :     for (i = 0; i < c->ach; i++) {
     380         107 :         c->audio_pkt[i].pos  = pos;
     381         107 :         c->audio_pkt[i].size = size;
     382         214 :         c->audio_pkt[i].pts  = c->abytes * 30000 * 8 /
     383         107 :                                c->ast[i]->codecpar->bit_rate;
     384         107 :         ppcm[i] = c->audio_buf[i];
     385             :     }
     386         638 :     if (c->ach)
     387         107 :         dv_extract_audio(buf, ppcm, c->sys);
     388             : 
     389             :     /* We work with 720p frames split in half, thus even frames have
     390             :      * channels 0,1 and odd 2,3. */
     391         638 :     if (c->sys->height == 720) {
     392           0 :         if (buf[1] & 0x0C) {
     393           0 :             c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
     394             :         } else {
     395           0 :             c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
     396           0 :             c->abytes           += size;
     397             :         }
     398             :     } else {
     399         638 :         c->abytes += size;
     400             :     }
     401             : 
     402             :     /* Now it's time to return video packet */
     403         638 :     size = dv_extract_video_info(c, buf);
     404         638 :     av_init_packet(pkt);
     405         638 :     pkt->data         = buf;
     406         638 :     pkt->pos          = pos;
     407         638 :     pkt->size         = size;
     408         638 :     pkt->flags       |= AV_PKT_FLAG_KEY;
     409         638 :     pkt->stream_index = c->vst->index;
     410         638 :     pkt->pts          = c->frames;
     411             : 
     412         638 :     c->frames++;
     413             : 
     414         638 :     return size;
     415             : }
     416             : 
     417         104 : static int64_t dv_frame_offset(AVFormatContext *s, DVDemuxContext *c,
     418             :                                int64_t timestamp, int flags)
     419             : {
     420             :     // FIXME: sys may be wrong if last dv_read_packet() failed (buffer is junk)
     421         104 :     const int frame_size = c->sys->frame_size;
     422             :     int64_t offset;
     423         104 :     int64_t size       = avio_size(s->pb) - s->internal->data_offset;
     424         104 :     int64_t max_offset = ((size - 1) / frame_size) * frame_size;
     425             : 
     426         104 :     offset = frame_size * timestamp;
     427             : 
     428         104 :     if (size >= 0 && offset > max_offset)
     429          31 :         offset = max_offset;
     430          73 :     else if (offset < 0)
     431          32 :         offset = 0;
     432             : 
     433         104 :     return offset + s->internal->data_offset;
     434             : }
     435             : 
     436         104 : void ff_dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)
     437             : {
     438         104 :     c->frames = frame_offset;
     439         104 :     if (c->ach) {
     440          26 :         if (c->sys) {
     441          26 :         c->abytes = av_rescale_q(c->frames, c->sys->time_base,
     442          26 :                                  (AVRational) { 8, c->ast[0]->codecpar->bit_rate });
     443             :         } else
     444           0 :             av_log(c->fctx, AV_LOG_ERROR, "cannot adjust audio bytes\n");
     445             :     }
     446         104 :     c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
     447         104 :     c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
     448         104 : }
     449             : 
     450             : /************************************************************
     451             :  * Implementation of the easiest DV storage of all -- raw DV.
     452             :  ************************************************************/
     453             : 
     454             : typedef struct RawDVContext {
     455             :     DVDemuxContext *dv_demux;
     456             :     uint8_t         buf[DV_MAX_FRAME_SIZE];
     457             : } RawDVContext;
     458             : 
     459          17 : static int dv_read_timecode(AVFormatContext *s) {
     460             :     int ret;
     461             :     char timecode[AV_TIMECODE_STR_SIZE];
     462          17 :     int64_t pos = avio_tell(s->pb);
     463             : 
     464             :     // Read 3 DIF blocks: Header block and 2 Subcode blocks.
     465          17 :     int partial_frame_size = 3 * 80;
     466          17 :     uint8_t *partial_frame = av_mallocz(sizeof(*partial_frame) *
     467             :                                         partial_frame_size);
     468             : 
     469          17 :     RawDVContext *c = s->priv_data;
     470          17 :     if (!partial_frame)
     471           0 :         return AVERROR(ENOMEM);
     472             : 
     473          17 :     ret = avio_read(s->pb, partial_frame, partial_frame_size);
     474          17 :     if (ret < 0)
     475           0 :         goto finish;
     476             : 
     477          17 :     if (ret < partial_frame_size) {
     478           0 :         ret = -1;
     479           0 :         goto finish;
     480             :     }
     481             : 
     482          17 :     ret = dv_extract_timecode(c->dv_demux, partial_frame, timecode);
     483          17 :     if (ret)
     484          17 :         av_dict_set(&s->metadata, "timecode", timecode, 0);
     485             :     else
     486           0 :         av_log(s, AV_LOG_ERROR, "Detected timecode is invalid\n");
     487             : 
     488          17 : finish:
     489          17 :     av_free(partial_frame);
     490          17 :     avio_seek(s->pb, pos, SEEK_SET);
     491          17 :     return ret;
     492             : }
     493             : 
     494          17 : static int dv_read_header(AVFormatContext *s)
     495             : {
     496          17 :     unsigned state, marker_pos = 0;
     497          17 :     RawDVContext *c = s->priv_data;
     498             : 
     499          17 :     c->dv_demux = avpriv_dv_init_demux(s);
     500          17 :     if (!c->dv_demux)
     501           0 :         return -1;
     502             : 
     503          17 :     state = avio_rb32(s->pb);
     504          34 :     while ((state & 0xffffff7f) != 0x1f07003f) {
     505           0 :         if (avio_feof(s->pb)) {
     506           0 :             av_log(s, AV_LOG_ERROR, "Cannot find DV header.\n");
     507           0 :             return -1;
     508             :         }
     509           0 :         if (state == 0x003f0700 || state == 0xff3f0700)
     510           0 :             marker_pos = avio_tell(s->pb);
     511           0 :         if (state == 0xff3f0701 && avio_tell(s->pb) - marker_pos == 80) {
     512           0 :             avio_seek(s->pb, -163, SEEK_CUR);
     513           0 :             state = avio_rb32(s->pb);
     514           0 :             break;
     515             :         }
     516           0 :         state = (state << 8) | avio_r8(s->pb);
     517             :     }
     518          17 :     AV_WB32(c->buf, state);
     519             : 
     520          34 :     if (avio_read(s->pb, c->buf + 4, DV_PROFILE_BYTES - 4) != DV_PROFILE_BYTES - 4 ||
     521          17 :         avio_seek(s->pb, -DV_PROFILE_BYTES, SEEK_CUR) < 0)
     522           0 :         return AVERROR(EIO);
     523             : 
     524          17 :     c->dv_demux->sys = av_dv_frame_profile(c->dv_demux->sys,
     525          17 :                                            c->buf,
     526             :                                            DV_PROFILE_BYTES);
     527          17 :     if (!c->dv_demux->sys) {
     528           0 :         av_log(s, AV_LOG_ERROR,
     529             :                "Can't determine profile of DV input stream.\n");
     530           0 :         return -1;
     531             :     }
     532             : 
     533          17 :     s->bit_rate = av_rescale_q(c->dv_demux->sys->frame_size,
     534          17 :                                (AVRational) { 8, 1 },
     535          17 :                                c->dv_demux->sys->time_base);
     536             : 
     537          17 :     if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
     538          17 :         dv_read_timecode(s);
     539             : 
     540          17 :     return 0;
     541             : }
     542             : 
     543         731 : static int dv_read_packet(AVFormatContext *s, AVPacket *pkt)
     544             : {
     545             :     int size;
     546         731 :     RawDVContext *c = s->priv_data;
     547             : 
     548         731 :     size = avpriv_dv_get_packet(c->dv_demux, pkt);
     549             : 
     550         731 :     if (size < 0) {
     551             :         int ret;
     552         650 :         int64_t pos = avio_tell(s->pb);
     553         650 :         if (!c->dv_demux->sys)
     554           0 :             return AVERROR(EIO);
     555         650 :         size = c->dv_demux->sys->frame_size;
     556         650 :         ret = avio_read(s->pb, c->buf, size);
     557         650 :         if (ret < 0) {
     558          12 :             return ret;
     559         638 :         } else if (ret == 0) {
     560           0 :             return AVERROR(EIO);
     561             :         }
     562             : 
     563         638 :         size = avpriv_dv_produce_packet(c->dv_demux, pkt, c->buf, size, pos);
     564             :     }
     565             : 
     566         719 :     return size;
     567             : }
     568             : 
     569         104 : static int dv_read_seek(AVFormatContext *s, int stream_index,
     570             :                         int64_t timestamp, int flags)
     571             : {
     572         104 :     RawDVContext *r   = s->priv_data;
     573         104 :     DVDemuxContext *c = r->dv_demux;
     574         104 :     int64_t offset    = dv_frame_offset(s, c, timestamp, flags);
     575             : 
     576         104 :     if (avio_seek(s->pb, offset, SEEK_SET) < 0)
     577           0 :         return -1;
     578             : 
     579         104 :     ff_dv_offset_reset(c, offset / c->sys->frame_size);
     580         104 :     return 0;
     581             : }
     582             : 
     583          17 : static int dv_read_close(AVFormatContext *s)
     584             : {
     585          17 :     RawDVContext *c = s->priv_data;
     586          17 :     av_freep(&c->dv_demux);
     587          17 :     return 0;
     588             : }
     589             : 
     590        5965 : static int dv_probe(AVProbeData *p)
     591             : {
     592        5965 :     unsigned marker_pos = 0;
     593             :     int i;
     594        5965 :     int matches           = 0;
     595        5965 :     int firstmatch        = 0;
     596        5965 :     int secondary_matches = 0;
     597             : 
     598        5965 :     if (p->buf_size < 5)
     599           0 :         return 0;
     600             : 
     601   126040173 :     for (i = 0; i < p->buf_size-4; i++) {
     602   126034208 :         unsigned state = AV_RB32(p->buf+i);
     603   126034208 :         if ((state & 0x0007f840) == 0x00070000) {
     604             :             // any section header, also with seq/chan num != 0,
     605             :             // should appear around every 12000 bytes, at least 10 per frame
     606      725786 :             if ((state & 0xff07ff7f) == 0x1f07003f) {
     607          20 :                 secondary_matches++;
     608          20 :                 if ((state & 0xffffff7f) == 0x1f07003f) {
     609          18 :                     matches++;
     610          18 :                     if (!i)
     611          17 :                         firstmatch = 1;
     612             :                 }
     613             :             }
     614      725786 :             if (state == 0x003f0700 || state == 0xff3f0700)
     615          24 :                 marker_pos = i;
     616      725786 :             if (state == 0xff3f0701 && i - marker_pos == 80)
     617          18 :                 matches++;
     618             :         }
     619             :     }
     620             : 
     621        5965 :     if (matches && p->buf_size / matches < 1024 * 1024) {
     622          18 :         if (matches > 4 || firstmatch ||
     623           0 :             (secondary_matches >= 10 &&
     624           0 :              p->buf_size / secondary_matches < 24000))
     625             :             // not max to avoid dv in mov to match
     626          17 :             return AVPROBE_SCORE_MAX * 3 / 4;
     627           1 :         return AVPROBE_SCORE_MAX / 4;
     628             :     }
     629        5947 :     return 0;
     630             : }
     631             : 
     632             : AVInputFormat ff_dv_demuxer = {
     633             :     .name           = "dv",
     634             :     .long_name      = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),
     635             :     .priv_data_size = sizeof(RawDVContext),
     636             :     .read_probe     = dv_probe,
     637             :     .read_header    = dv_read_header,
     638             :     .read_packet    = dv_read_packet,
     639             :     .read_close     = dv_read_close,
     640             :     .read_seek      = dv_read_seek,
     641             :     .extensions     = "dv,dif",
     642             : };

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