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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 
00129     /* for each DIF channel */
00130     for (chan = 0; chan < sys->n_difchan; chan++) {
00131         /* next stereo channel (50Mbps and 100Mbps only) */
00132         pcm = ppcm[ipcm++];
00133         if (!pcm)
00134             break;
00135 
00136         /* for each DIF segment */
00137         for (i = 0; i < sys->difseg_size; i++) {
00138             frame += 6 * 80; /* skip DIF segment header */
00139             if (quant == 1 && i == half_ch) {
00140                 /* next stereo channel (12bit mode only) */
00141                 pcm = ppcm[ipcm++];
00142                 if (!pcm)
00143                     break;
00144             }
00145 
00146             /* for each AV sequence */
00147             for (j = 0; j < 9; j++) {
00148                 for (d = 8; d < 80; d += 2) {
00149                     if (quant == 0) {  /* 16bit quantization */
00150                         of = sys->audio_shuffle[i][j] + (d - 8) / 2 * sys->audio_stride;
00151                         if (of*2 >= size)
00152                             continue;
00153 
00154                         pcm[of*2]   = frame[d+1]; // FIXME: maybe we have to admit
00155                         pcm[of*2+1] = frame[d];   //        that DV is a big-endian PCM
00156                         if (pcm[of*2+1] == 0x80 && pcm[of*2] == 0x00)
00157                             pcm[of*2+1] = 0;
00158                     } else {           /* 12bit quantization */
00159                         lc = ((uint16_t)frame[d]   << 4) |
00160                              ((uint16_t)frame[d+2] >> 4);
00161                         rc = ((uint16_t)frame[d+1] << 4) |
00162                              ((uint16_t)frame[d+2] & 0x0f);
00163                         lc = (lc == 0x800 ? 0 : dv_audio_12to16(lc));
00164                         rc = (rc == 0x800 ? 0 : dv_audio_12to16(rc));
00165 
00166                         of = sys->audio_shuffle[i%half_ch][j] + (d - 8) / 3 * sys->audio_stride;
00167                         if (of*2 >= size)
00168                             continue;
00169 
00170                         pcm[of*2]   = lc & 0xff; // FIXME: maybe we have to admit
00171                         pcm[of*2+1] = lc >> 8;   //        that DV is a big-endian PCM
00172                         of = sys->audio_shuffle[i%half_ch+half_ch][j] +
00173                             (d - 8) / 3 * sys->audio_stride;
00174                         pcm[of*2]   = rc & 0xff; // FIXME: maybe we have to admit
00175                         pcm[of*2+1] = rc >> 8;   //        that DV is a big-endian PCM
00176                         ++d;
00177                     }
00178                 }
00179 
00180                 frame += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
00181             }
00182         }
00183     }
00184 
00185     return size;
00186 }
00187 
00188 static int dv_extract_audio_info(DVDemuxContext* c, uint8_t* frame)
00189 {
00190     const uint8_t* as_pack;
00191     int freq, stype, smpls, quant, i, ach;
00192 
00193     as_pack = dv_extract_pack(frame, dv_audio_source);
00194     if (!as_pack || !c->sys) {    /* No audio ? */
00195         c->ach = 0;
00196         return 0;
00197     }
00198 
00199     smpls =  as_pack[1] & 0x3f;       /* samples in this frame - min. samples */
00200     freq  = (as_pack[4] >> 3) & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
00201     stype = (as_pack[3] & 0x1f);      /* 0 - 2CH, 2 - 4CH, 3 - 8CH */
00202     quant =  as_pack[4] & 0x07;       /* 0 - 16bit linear, 1 - 12bit nonlinear */
00203 
00204     if (stype > 3) {
00205         av_log(c->fctx, AV_LOG_ERROR, "stype %d is invalid\n", stype);
00206         c->ach = 0;
00207         return 0;
00208     }
00209 
00210     /* note: ach counts PAIRS of channels (i.e. stereo channels) */
00211     ach = ((int[4]){  1,  0,  2,  4})[stype];
00212     if (ach == 1 && quant && freq == 2)
00213         ach = 2;
00214 
00215     /* Dynamic handling of the audio streams in DV */
00216     for (i = 0; i < ach; i++) {
00217        if (!c->ast[i]) {
00218            c->ast[i] = av_new_stream(c->fctx, 0);
00219            if (!c->ast[i])
00220                break;
00221            av_set_pts_info(c->ast[i], 64, 1, 30000);
00222            c->ast[i]->codec->codec_type = CODEC_TYPE_AUDIO;
00223            c->ast[i]->codec->codec_id   = CODEC_ID_PCM_S16LE;
00224 
00225            av_init_packet(&c->audio_pkt[i]);
00226            c->audio_pkt[i].size         = 0;
00227            c->audio_pkt[i].data         = c->audio_buf[i];
00228            c->audio_pkt[i].stream_index = c->ast[i]->index;
00229            c->audio_pkt[i].flags       |= PKT_FLAG_KEY;
00230        }
00231        c->ast[i]->codec->sample_rate = dv_audio_frequency[freq];
00232        c->ast[i]->codec->channels    = 2;
00233        c->ast[i]->codec->bit_rate    = 2 * dv_audio_frequency[freq] * 16;
00234        c->ast[i]->start_time         = 0;
00235     }
00236     c->ach = i;
00237 
00238     return (c->sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */;
00239 }
00240 
00241 static int dv_extract_video_info(DVDemuxContext *c, uint8_t* frame)
00242 {
00243     const uint8_t* vsc_pack;
00244     AVCodecContext* avctx;
00245     int apt, is16_9;
00246     int size = 0;
00247 
00248     if (c->sys) {
00249         avctx = c->vst->codec;
00250 
00251         av_set_pts_info(c->vst, 64, c->sys->time_base.num,
00252                         c->sys->time_base.den);
00253         avctx->time_base= c->sys->time_base;
00254         if (!avctx->width){
00255             avctx->width = c->sys->width;
00256             avctx->height = c->sys->height;
00257         }
00258         avctx->pix_fmt = c->sys->pix_fmt;
00259 
00260         /* finding out SAR is a little bit messy */
00261         vsc_pack = dv_extract_pack(frame, dv_video_control);
00262         apt      = frame[4] & 0x07;
00263         is16_9   = (vsc_pack && ((vsc_pack[2] & 0x07) == 0x02 ||
00264                                 (!apt && (vsc_pack[2] & 0x07) == 0x07)));
00265         c->vst->sample_aspect_ratio = c->sys->sar[is16_9];
00266         avctx->bit_rate = av_rescale_q(c->sys->frame_size, (AVRational){8,1},
00267                                        c->sys->time_base);
00268         size = c->sys->frame_size;
00269     }
00270     return size;
00271 }
00272 
00273 /*
00274  * The following 3 functions constitute our interface to the world
00275  */
00276 
00277 DVDemuxContext* dv_init_demux(AVFormatContext *s)
00278 {
00279     DVDemuxContext *c;
00280 
00281     c = av_mallocz(sizeof(DVDemuxContext));
00282     if (!c)
00283         return NULL;
00284 
00285     c->vst = av_new_stream(s, 0);
00286     if (!c->vst) {
00287         av_free(c);
00288         return NULL;
00289     }
00290 
00291     c->sys  = NULL;
00292     c->fctx = s;
00293     memset(c->ast, 0, sizeof(c->ast));
00294     c->ach    = 0;
00295     c->frames = 0;
00296     c->abytes = 0;
00297 
00298     c->vst->codec->codec_type = CODEC_TYPE_VIDEO;
00299     c->vst->codec->codec_id   = CODEC_ID_DVVIDEO;
00300     c->vst->codec->bit_rate   = 25000000;
00301     c->vst->start_time        = 0;
00302 
00303     return c;
00304 }
00305 
00306 int dv_get_packet(DVDemuxContext *c, AVPacket *pkt)
00307 {
00308     int size = -1;
00309     int i;
00310 
00311     for (i = 0; i < c->ach; i++) {
00312        if (c->ast[i] && c->audio_pkt[i].size) {
00313            *pkt = c->audio_pkt[i];
00314            c->audio_pkt[i].size = 0;
00315            size = pkt->size;
00316            break;
00317        }
00318     }
00319 
00320     return size;
00321 }
00322 
00323 int dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,
00324                       uint8_t* buf, int buf_size)
00325 {
00326     int size, i;
00327     uint8_t *ppcm[4] = {0};
00328 
00329     if (buf_size < DV_PROFILE_BYTES ||
00330         !(c->sys = dv_frame_profile(c->sys, buf, buf_size)) ||
00331         buf_size < c->sys->frame_size) {
00332           return -1;   /* Broken frame, or not enough data */
00333     }
00334 
00335     /* Queueing audio packet */
00336     /* FIXME: in case of no audio/bad audio we have to do something */
00337     size = dv_extract_audio_info(c, buf);
00338     for (i = 0; i < c->ach; i++) {
00339        c->audio_pkt[i].size = size;
00340        c->audio_pkt[i].pts  = c->abytes * 30000*8 / c->ast[i]->codec->bit_rate;
00341        ppcm[i] = c->audio_buf[i];
00342     }
00343     if (c->ach)
00344         dv_extract_audio(buf, ppcm, c->sys);
00345     c->abytes += size;
00346 
00347     /* We work with 720p frames split in half, thus even frames have
00348      * channels 0,1 and odd 2,3. */
00349     if (c->sys->height == 720) {
00350         if (buf[1] & 0x0C)
00351             c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
00352         else
00353             c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
00354     }
00355 
00356     /* Now it's time to return video packet */
00357     size = dv_extract_video_info(c, buf);
00358     av_init_packet(pkt);
00359     pkt->data         = buf;
00360     pkt->size         = size;
00361     pkt->flags       |= PKT_FLAG_KEY;
00362     pkt->stream_index = c->vst->id;
00363     pkt->pts          = c->frames;
00364 
00365     c->frames++;
00366 
00367     return size;
00368 }
00369 
00370 static int64_t dv_frame_offset(AVFormatContext *s, DVDemuxContext *c,
00371                               int64_t timestamp, int flags)
00372 {
00373     // FIXME: sys may be wrong if last dv_read_packet() failed (buffer is junk)
00374     const DVprofile* sys = dv_codec_profile(c->vst->codec);
00375     int64_t offset;
00376     int64_t size = url_fsize(s->pb);
00377     int64_t max_offset = ((size-1) / sys->frame_size) * sys->frame_size;
00378 
00379     offset = sys->frame_size * timestamp;
00380 
00381     if (offset > max_offset) offset = max_offset;
00382     else if (offset < 0) offset = 0;
00383 
00384     return offset;
00385 }
00386 
00387 void dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)
00388 {
00389     c->frames= frame_offset;
00390     if (c->ach)
00391         c->abytes= av_rescale_q(c->frames, c->sys->time_base,
00392                                 (AVRational){8, c->ast[0]->codec->bit_rate});
00393     c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
00394     c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
00395 }
00396 
00397 /************************************************************
00398  * Implementation of the easiest DV storage of all -- raw DV.
00399  ************************************************************/
00400 
00401 typedef struct RawDVContext {
00402     DVDemuxContext* dv_demux;
00403     uint8_t         buf[DV_MAX_FRAME_SIZE];
00404 } RawDVContext;
00405 
00406 static int dv_read_header(AVFormatContext *s,
00407                           AVFormatParameters *ap)
00408 {
00409     unsigned state;
00410     RawDVContext *c = s->priv_data;
00411 
00412     c->dv_demux = dv_init_demux(s);
00413     if (!c->dv_demux)
00414         return -1;
00415 
00416     state = get_be32(s->pb);
00417     while ((state & 0xffffff7f) != 0x1f07003f) {
00418         if (url_feof(s->pb)) {
00419             av_log(s, AV_LOG_ERROR, "Cannot find DV header.\n");
00420             return -1;
00421         }
00422         state = (state << 8) | get_byte(s->pb);
00423     }
00424     AV_WB32(c->buf, state);
00425 
00426     if (get_buffer(s->pb, c->buf + 4, DV_PROFILE_BYTES - 4) <= 0 ||
00427         url_fseek(s->pb, -DV_PROFILE_BYTES, SEEK_CUR) < 0)
00428         return AVERROR(EIO);
00429 
00430     c->dv_demux->sys = dv_frame_profile(c->dv_demux->sys, c->buf, DV_PROFILE_BYTES);
00431     if (!c->dv_demux->sys) {
00432         av_log(s, AV_LOG_ERROR, "Can't determine profile of DV input stream.\n");
00433         return -1;
00434     }
00435 
00436     s->bit_rate = av_rescale_q(c->dv_demux->sys->frame_size, (AVRational){8,1},
00437                                c->dv_demux->sys->time_base);
00438 
00439     return 0;
00440 }
00441 
00442 
00443 static int dv_read_packet(AVFormatContext *s, AVPacket *pkt)
00444 {
00445     int size;
00446     RawDVContext *c = s->priv_data;
00447 
00448     size = dv_get_packet(c->dv_demux, pkt);
00449 
00450     if (size < 0) {
00451         if (!c->dv_demux->sys)
00452             return AVERROR(EIO);
00453         size = c->dv_demux->sys->frame_size;
00454         if (get_buffer(s->pb, c->buf, size) <= 0)
00455             return AVERROR(EIO);
00456 
00457         size = dv_produce_packet(c->dv_demux, pkt, c->buf, size);
00458     }
00459 
00460     return size;
00461 }
00462 
00463 static int dv_read_seek(AVFormatContext *s, int stream_index,
00464                        int64_t timestamp, int flags)
00465 {
00466     RawDVContext *r   = s->priv_data;
00467     DVDemuxContext *c = r->dv_demux;
00468     int64_t offset    = dv_frame_offset(s, c, timestamp, flags);
00469 
00470     dv_offset_reset(c, offset / c->sys->frame_size);
00471 
00472     offset = url_fseek(s->pb, offset, SEEK_SET);
00473     return (offset < 0) ? offset : 0;
00474 }
00475 
00476 static int dv_read_close(AVFormatContext *s)
00477 {
00478     RawDVContext *c = s->priv_data;
00479     av_free(c->dv_demux);
00480     return 0;
00481 }
00482 
00483 static int dv_probe(AVProbeData *p)
00484 {
00485     unsigned state;
00486     int i;
00487 
00488     if (p->buf_size < 5)
00489         return 0;
00490 
00491     state = AV_RB32(p->buf);
00492     for (i = 4; i < p->buf_size; i++) {
00493         if ((state & 0xffffff7f) == 0x1f07003f)
00494             return AVPROBE_SCORE_MAX*3/4; // not max to avoid dv in mov to match
00495         state = (state << 8) | p->buf[i];
00496     }
00497 
00498     return 0;
00499 }
00500 
00501 #if CONFIG_DV_DEMUXER
00502 AVInputFormat dv_demuxer = {
00503     "dv",
00504     NULL_IF_CONFIG_SMALL("DV video format"),
00505     sizeof(RawDVContext),
00506     dv_probe,
00507     dv_read_header,
00508     dv_read_packet,
00509     dv_read_close,
00510     dv_read_seek,
00511     .extensions = "dv,dif",
00512 };
00513 #endif

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