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libavformat/dv.c

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00001 /*
00002  * General DV muxer/demuxer
00003  * Copyright (c) 2003 Roman Shaposhnik
00004  *
00005  * Many thanks to Dan Dennedy <dan@dennedy.org> for providing wealth
00006  * of DV technical info.
00007  *
00008  * Raw DV format
00009  * Copyright (c) 2002 Fabrice Bellard
00010  *
00011  * 50 Mbps (DVCPRO50) and 100 Mbps (DVCPRO HD) support
00012  * Copyright (c) 2006 Daniel Maas <dmaas@maasdigital.com>
00013  * Funded by BBC Research & Development
00014  *
00015  * This file is part of FFmpeg.
00016  *
00017  * FFmpeg is free software; you can redistribute it and/or
00018  * modify it under the terms of the GNU Lesser General Public
00019  * License as published by the Free Software Foundation; either
00020  * version 2.1 of the License, or (at your option) any later version.
00021  *
00022  * FFmpeg is distributed in the hope that it will be useful,
00023  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00024  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00025  * Lesser General Public License for more details.
00026  *
00027  * You should have received a copy of the GNU Lesser General Public
00028  * License along with FFmpeg; if not, write to the Free Software
00029  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00030  */
00031 #include <time.h>
00032 #include "avformat.h"
00033 #include "libavcodec/dvdata.h"
00034 #include "libavutil/intreadwrite.h"
00035 #include "dv.h"
00036 
00037 struct DVDemuxContext {
00038     const DVprofile*  sys;    /* Current DV profile. E.g.: 525/60, 625/50 */
00039     AVFormatContext*  fctx;
00040     AVStream*         vst;
00041     AVStream*         ast[4];
00042     AVPacket          audio_pkt[4];
00043     uint8_t           audio_buf[4][8192];
00044     int               ach;
00045     int               frames;
00046     uint64_t          abytes;
00047 };
00048 
00049 static inline uint16_t dv_audio_12to16(uint16_t sample)
00050 {
00051     uint16_t shift, result;
00052 
00053     sample = (sample < 0x800) ? sample : sample | 0xf000;
00054     shift  = (sample & 0xf00) >> 8;
00055 
00056     if (shift < 0x2 || shift > 0xd) {
00057         result = sample;
00058     } else if (shift < 0x8) {
00059         shift--;
00060         result = (sample - (256 * shift)) << shift;
00061     } else {
00062         shift = 0xe - shift;
00063         result = ((sample + ((256 * shift) + 1)) << shift) - 1;
00064     }
00065 
00066     return result;
00067 }
00068 
00069 /*
00070  * This is the dumbest implementation of all -- it simply looks at
00071  * a fixed offset and if pack isn't there -- fails. We might want
00072  * to have a fallback mechanism for complete search of missing packs.
00073  */
00074 static const uint8_t* dv_extract_pack(uint8_t* frame, enum dv_pack_type t)
00075 {
00076     int offs;
00077 
00078     switch (t) {
00079     case dv_audio_source:
00080         offs = (80*6 + 80*16*3 + 3);
00081         break;
00082     case dv_audio_control:
00083         offs = (80*6 + 80*16*4 + 3);
00084         break;
00085     case dv_video_control:
00086         offs = (80*5 + 48 + 5);
00087         break;
00088     default:
00089         return NULL;
00090     }
00091 
00092     return frame[offs] == t ? &frame[offs] : NULL;
00093 }
00094 
00095 /*
00096  * There's a couple of assumptions being made here:
00097  * 1. By default we silence erroneous (0x8000/16bit 0x800/12bit) audio samples.
00098  *    We can pass them upwards when ffmpeg will be ready to deal with them.
00099  * 2. We don't do software emphasis.
00100  * 3. Audio is always returned as 16bit linear samples: 12bit nonlinear samples
00101  *    are converted into 16bit linear ones.
00102  */
00103 static int dv_extract_audio(uint8_t* frame, uint8_t* ppcm[4],
00104                             const DVprofile *sys)
00105 {
00106     int size, chan, i, j, d, of, smpls, freq, quant, half_ch;
00107     uint16_t lc, rc;
00108     const uint8_t* as_pack;
00109     uint8_t *pcm, ipcm;
00110 
00111     as_pack = dv_extract_pack(frame, dv_audio_source);
00112     if (!as_pack)    /* No audio ? */
00113         return 0;
00114 
00115     smpls =  as_pack[1] & 0x3f;       /* samples in this frame - min. samples */
00116     freq  = (as_pack[4] >> 3) & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
00117     quant =  as_pack[4] & 0x07;       /* 0 - 16bit linear, 1 - 12bit nonlinear */
00118 
00119     if (quant > 1)
00120         return -1; /* unsupported quantization */
00121 
00122     size = (sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
00123     half_ch = sys->difseg_size / 2;
00124 
00125     /* We work with 720p frames split in half, thus even frames have
00126      * channels 0,1 and odd 2,3. */
00127     ipcm = (sys->height == 720 && !(frame[1] & 0x0C)) ? 2 : 0;
00128     pcm  = ppcm[ipcm++];
00129 
00130     /* for each DIF channel */
00131     for (chan = 0; chan < sys->n_difchan; chan++) {
00132         /* for each DIF segment */
00133         for (i = 0; i < sys->difseg_size; i++) {
00134             frame += 6 * 80; /* skip DIF segment header */
00135             if (quant == 1 && i == half_ch) {
00136                 /* next stereo channel (12bit mode only) */
00137                 pcm = ppcm[ipcm++];
00138                 if (!pcm)
00139                     break;
00140             }
00141 
00142             /* for each AV sequence */
00143             for (j = 0; j < 9; j++) {
00144                 for (d = 8; d < 80; d += 2) {
00145                     if (quant == 0) {  /* 16bit quantization */
00146                         of = sys->audio_shuffle[i][j] + (d - 8) / 2 * sys->audio_stride;
00147                         if (of*2 >= size)
00148                             continue;
00149 
00150                         pcm[of*2]   = frame[d+1]; // FIXME: maybe we have to admit
00151                         pcm[of*2+1] = frame[d];   //        that DV is a big-endian PCM
00152                         if (pcm[of*2+1] == 0x80 && pcm[of*2] == 0x00)
00153                             pcm[of*2+1] = 0;
00154                     } else {           /* 12bit quantization */
00155                         lc = ((uint16_t)frame[d]   << 4) |
00156                              ((uint16_t)frame[d+2] >> 4);
00157                         rc = ((uint16_t)frame[d+1] << 4) |
00158                              ((uint16_t)frame[d+2] & 0x0f);
00159                         lc = (lc == 0x800 ? 0 : dv_audio_12to16(lc));
00160                         rc = (rc == 0x800 ? 0 : dv_audio_12to16(rc));
00161 
00162                         of = sys->audio_shuffle[i%half_ch][j] + (d - 8) / 3 * sys->audio_stride;
00163                         if (of*2 >= size)
00164                             continue;
00165 
00166                         pcm[of*2]   = lc & 0xff; // FIXME: maybe we have to admit
00167                         pcm[of*2+1] = lc >> 8;   //        that DV is a big-endian PCM
00168                         of = sys->audio_shuffle[i%half_ch+half_ch][j] +
00169                             (d - 8) / 3 * sys->audio_stride;
00170                         pcm[of*2]   = rc & 0xff; // FIXME: maybe we have to admit
00171                         pcm[of*2+1] = rc >> 8;   //        that DV is a big-endian PCM
00172                         ++d;
00173                     }
00174                 }
00175 
00176                 frame += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
00177             }
00178         }
00179 
00180         /* next stereo channel (50Mbps and 100Mbps only) */
00181         pcm = ppcm[ipcm++];
00182         if (!pcm)
00183             break;
00184     }
00185 
00186     return size;
00187 }
00188 
00189 static int dv_extract_audio_info(DVDemuxContext* c, uint8_t* frame)
00190 {
00191     const uint8_t* as_pack;
00192     int freq, stype, smpls, quant, i, ach;
00193 
00194     as_pack = dv_extract_pack(frame, dv_audio_source);
00195     if (!as_pack || !c->sys) {    /* No audio ? */
00196         c->ach = 0;
00197         return 0;
00198     }
00199 
00200     smpls =  as_pack[1] & 0x3f;       /* samples in this frame - min. samples */
00201     freq  = (as_pack[4] >> 3) & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
00202     stype = (as_pack[3] & 0x1f);      /* 0 - 2CH, 2 - 4CH, 3 - 8CH */
00203     quant =  as_pack[4] & 0x07;       /* 0 - 16bit linear, 1 - 12bit nonlinear */
00204 
00205     /* note: ach counts PAIRS of channels (i.e. stereo channels) */
00206     ach = ((int[4]){  1,  0,  2,  4})[stype];
00207     if (ach == 1 && quant && freq == 2)
00208         ach = 2;
00209 
00210     /* Dynamic handling of the audio streams in DV */
00211     for (i = 0; i < ach; i++) {
00212        if (!c->ast[i]) {
00213            c->ast[i] = av_new_stream(c->fctx, 0);
00214            if (!c->ast[i])
00215                break;
00216            av_set_pts_info(c->ast[i], 64, 1, 30000);
00217            c->ast[i]->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00218            c->ast[i]->codec->codec_id   = CODEC_ID_PCM_S16LE;
00219 
00220            av_init_packet(&c->audio_pkt[i]);
00221            c->audio_pkt[i].size         = 0;
00222            c->audio_pkt[i].data         = c->audio_buf[i];
00223            c->audio_pkt[i].stream_index = c->ast[i]->index;
00224            c->audio_pkt[i].flags       |= AV_PKT_FLAG_KEY;
00225        }
00226        c->ast[i]->codec->sample_rate = dv_audio_frequency[freq];
00227        c->ast[i]->codec->channels    = 2;
00228        c->ast[i]->codec->bit_rate    = 2 * dv_audio_frequency[freq] * 16;
00229        c->ast[i]->start_time         = 0;
00230     }
00231     c->ach = i;
00232 
00233     return (c->sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */;
00234 }
00235 
00236 static int dv_extract_video_info(DVDemuxContext *c, uint8_t* frame)
00237 {
00238     const uint8_t* vsc_pack;
00239     AVCodecContext* avctx;
00240     int apt, is16_9;
00241     int size = 0;
00242 
00243     if (c->sys) {
00244         avctx = c->vst->codec;
00245 
00246         av_set_pts_info(c->vst, 64, c->sys->time_base.num,
00247                         c->sys->time_base.den);
00248         avctx->time_base= c->sys->time_base;
00249         if (!avctx->width){
00250             avctx->width = c->sys->width;
00251             avctx->height = c->sys->height;
00252         }
00253         avctx->pix_fmt = c->sys->pix_fmt;
00254 
00255         /* finding out SAR is a little bit messy */
00256         vsc_pack = dv_extract_pack(frame, dv_video_control);
00257         apt      = frame[4] & 0x07;
00258         is16_9   = (vsc_pack && ((vsc_pack[2] & 0x07) == 0x02 ||
00259                                 (!apt && (vsc_pack[2] & 0x07) == 0x07)));
00260         c->vst->sample_aspect_ratio = c->sys->sar[is16_9];
00261         avctx->bit_rate = av_rescale_q(c->sys->frame_size, (AVRational){8,1},
00262                                        c->sys->time_base);
00263         size = c->sys->frame_size;
00264     }
00265     return size;
00266 }
00267 
00268 /*
00269  * The following 3 functions constitute our interface to the world
00270  */
00271 
00272 DVDemuxContext* dv_init_demux(AVFormatContext *s)
00273 {
00274     DVDemuxContext *c;
00275 
00276     c = av_mallocz(sizeof(DVDemuxContext));
00277     if (!c)
00278         return NULL;
00279 
00280     c->vst = av_new_stream(s, 0);
00281     if (!c->vst) {
00282         av_free(c);
00283         return NULL;
00284     }
00285 
00286     c->sys  = NULL;
00287     c->fctx = s;
00288     memset(c->ast, 0, sizeof(c->ast));
00289     c->ach    = 0;
00290     c->frames = 0;
00291     c->abytes = 0;
00292 
00293     c->vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00294     c->vst->codec->codec_id   = CODEC_ID_DVVIDEO;
00295     c->vst->codec->bit_rate   = 25000000;
00296     c->vst->start_time        = 0;
00297 
00298     return c;
00299 }
00300 
00301 int dv_get_packet(DVDemuxContext *c, AVPacket *pkt)
00302 {
00303     int size = -1;
00304     int i;
00305 
00306     for (i = 0; i < c->ach; i++) {
00307        if (c->ast[i] && c->audio_pkt[i].size) {
00308            *pkt = c->audio_pkt[i];
00309            c->audio_pkt[i].size = 0;
00310            size = pkt->size;
00311            break;
00312        }
00313     }
00314 
00315     return size;
00316 }
00317 
00318 int dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,
00319                       uint8_t* buf, int buf_size)
00320 {
00321     int size, i;
00322     uint8_t *ppcm[4] = {0};
00323 
00324     if (buf_size < DV_PROFILE_BYTES ||
00325         !(c->sys = ff_dv_frame_profile(c->sys, buf, buf_size)) ||
00326         buf_size < c->sys->frame_size) {
00327           return -1;   /* Broken frame, or not enough data */
00328     }
00329 
00330     /* Queueing audio packet */
00331     /* FIXME: in case of no audio/bad audio we have to do something */
00332     size = dv_extract_audio_info(c, buf);
00333     for (i = 0; i < c->ach; i++) {
00334        c->audio_pkt[i].size = size;
00335        c->audio_pkt[i].pts  = c->abytes * 30000*8 / c->ast[i]->codec->bit_rate;
00336        ppcm[i] = c->audio_buf[i];
00337     }
00338     dv_extract_audio(buf, ppcm, c->sys);
00339 
00340     /* We work with 720p frames split in half, thus even frames have
00341      * channels 0,1 and odd 2,3. */
00342     if (c->sys->height == 720) {
00343         if (buf[1] & 0x0C) {
00344             c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
00345         } else {
00346             c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
00347             c->abytes += size;
00348         }
00349     } else {
00350         c->abytes += size;
00351     }
00352 
00353     /* Now it's time to return video packet */
00354     size = dv_extract_video_info(c, buf);
00355     av_init_packet(pkt);
00356     pkt->data         = buf;
00357     pkt->size         = size;
00358     pkt->flags       |= AV_PKT_FLAG_KEY;
00359     pkt->stream_index = c->vst->id;
00360     pkt->pts          = c->frames;
00361 
00362     c->frames++;
00363 
00364     return size;
00365 }
00366 
00367 static int64_t dv_frame_offset(AVFormatContext *s, DVDemuxContext *c,
00368                               int64_t timestamp, int flags)
00369 {
00370     // FIXME: sys may be wrong if last dv_read_packet() failed (buffer is junk)
00371     const DVprofile* sys = ff_dv_codec_profile(c->vst->codec);
00372     int64_t offset;
00373     int64_t size = url_fsize(s->pb);
00374     int64_t max_offset = ((size-1) / sys->frame_size) * sys->frame_size;
00375 
00376     offset = sys->frame_size * timestamp;
00377 
00378     if (size >= 0 && offset > max_offset) offset = max_offset;
00379     else if (offset < 0) offset = 0;
00380 
00381     return offset;
00382 }
00383 
00384 void dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)
00385 {
00386     c->frames= frame_offset;
00387     if (c->ach)
00388         c->abytes= av_rescale_q(c->frames, c->sys->time_base,
00389                                 (AVRational){8, c->ast[0]->codec->bit_rate});
00390     c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
00391     c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
00392 }
00393 
00394 /************************************************************
00395  * Implementation of the easiest DV storage of all -- raw DV.
00396  ************************************************************/
00397 
00398 typedef struct RawDVContext {
00399     DVDemuxContext* dv_demux;
00400     uint8_t         buf[DV_MAX_FRAME_SIZE];
00401 } RawDVContext;
00402 
00403 static int dv_read_header(AVFormatContext *s,
00404                           AVFormatParameters *ap)
00405 {
00406     unsigned state, marker_pos = 0;
00407     RawDVContext *c = s->priv_data;
00408 
00409     c->dv_demux = dv_init_demux(s);
00410     if (!c->dv_demux)
00411         return -1;
00412 
00413     state = get_be32(s->pb);
00414     while ((state & 0xffffff7f) != 0x1f07003f) {
00415         if (url_feof(s->pb)) {
00416             av_log(s, AV_LOG_ERROR, "Cannot find DV header.\n");
00417             return -1;
00418         }
00419         if (state == 0x003f0700 || state == 0xff3f0700)
00420             marker_pos = url_ftell(s->pb);
00421         if (state == 0xff3f0701 && url_ftell(s->pb) - marker_pos == 80) {
00422             url_fseek(s->pb, -163, SEEK_CUR);
00423             state = get_be32(s->pb);
00424             break;
00425         }
00426         state = (state << 8) | get_byte(s->pb);
00427     }
00428     AV_WB32(c->buf, state);
00429 
00430     if (get_buffer(s->pb, c->buf + 4, DV_PROFILE_BYTES - 4) <= 0 ||
00431         url_fseek(s->pb, -DV_PROFILE_BYTES, SEEK_CUR) < 0)
00432         return AVERROR(EIO);
00433 
00434     c->dv_demux->sys = ff_dv_frame_profile(c->dv_demux->sys, c->buf, DV_PROFILE_BYTES);
00435     if (!c->dv_demux->sys) {
00436         av_log(s, AV_LOG_ERROR, "Can't determine profile of DV input stream.\n");
00437         return -1;
00438     }
00439 
00440     s->bit_rate = av_rescale_q(c->dv_demux->sys->frame_size, (AVRational){8,1},
00441                                c->dv_demux->sys->time_base);
00442 
00443     return 0;
00444 }
00445 
00446 
00447 static int dv_read_packet(AVFormatContext *s, AVPacket *pkt)
00448 {
00449     int size;
00450     RawDVContext *c = s->priv_data;
00451 
00452     size = dv_get_packet(c->dv_demux, pkt);
00453 
00454     if (size < 0) {
00455         if (!c->dv_demux->sys)
00456             return AVERROR(EIO);
00457         size = c->dv_demux->sys->frame_size;
00458         if (get_buffer(s->pb, c->buf, size) <= 0)
00459             return AVERROR(EIO);
00460 
00461         size = dv_produce_packet(c->dv_demux, pkt, c->buf, size);
00462     }
00463 
00464     return size;
00465 }
00466 
00467 static int dv_read_seek(AVFormatContext *s, int stream_index,
00468                        int64_t timestamp, int flags)
00469 {
00470     RawDVContext *r   = s->priv_data;
00471     DVDemuxContext *c = r->dv_demux;
00472     int64_t offset    = dv_frame_offset(s, c, timestamp, flags);
00473 
00474     dv_offset_reset(c, offset / c->sys->frame_size);
00475 
00476     offset = url_fseek(s->pb, offset, SEEK_SET);
00477     return (offset < 0) ? offset : 0;
00478 }
00479 
00480 static int dv_read_close(AVFormatContext *s)
00481 {
00482     RawDVContext *c = s->priv_data;
00483     av_free(c->dv_demux);
00484     return 0;
00485 }
00486 
00487 static int dv_probe(AVProbeData *p)
00488 {
00489     unsigned state, marker_pos = 0;
00490     int i;
00491     int matches = 0;
00492     int secondary_matches = 0;
00493 
00494     if (p->buf_size < 5)
00495         return 0;
00496 
00497     state = AV_RB32(p->buf);
00498     for (i = 4; i < p->buf_size; i++) {
00499         if ((state & 0xffffff7f) == 0x1f07003f)
00500             matches++;
00501         // any section header, also with seq/chan num != 0,
00502         // should appear around every 12000 bytes, at least 10 per frame
00503         if ((state & 0xff07ff7f) == 0x1f07003f)
00504             secondary_matches++;
00505         if (state == 0x003f0700 || state == 0xff3f0700)
00506             marker_pos = i;
00507         if (state == 0xff3f0701 && i - marker_pos == 80)
00508             matches++;
00509         state = (state << 8) | p->buf[i];
00510     }
00511 
00512     if (matches && p->buf_size / matches < 1024*1024) {
00513         if (matches > 4 || (secondary_matches >= 10 && p->buf_size / secondary_matches < 24000))
00514             return AVPROBE_SCORE_MAX*3/4; // not max to avoid dv in mov to match
00515         return AVPROBE_SCORE_MAX/4;
00516     }
00517     return 0;
00518 }
00519 
00520 #if CONFIG_DV_DEMUXER
00521 AVInputFormat dv_demuxer = {
00522     "dv",
00523     NULL_IF_CONFIG_SMALL("DV video format"),
00524     sizeof(RawDVContext),
00525     dv_probe,
00526     dv_read_header,
00527     dv_read_packet,
00528     dv_read_close,
00529     dv_read_seek,
00530     .extensions = "dv,dif",
00531 };
00532 #endif

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