2 * General DV muxer/demuxer
3 * Copyright (c) 2003 Roman Shaposhnik
5 * Many thanks to Dan Dennedy <dan@dennedy.org> for providing wealth
6 * of DV technical info.
9 * Copyright (c) 2002 Fabrice Bellard.
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
15 * This file is part of FFmpeg.
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.
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.
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
33 #include "libavcodec/dvdata.h"
36 struct DVDemuxContext {
37 const DVprofile* sys; /* Current DV profile. E.g.: 525/60, 625/50 */
38 AVFormatContext* fctx;
41 AVPacket audio_pkt[4];
42 uint8_t audio_buf[4][8192];
48 static inline uint16_t dv_audio_12to16(uint16_t sample)
50 uint16_t shift, result;
52 sample = (sample < 0x800) ? sample : sample | 0xf000;
53 shift = (sample & 0xf00) >> 8;
55 if (shift < 0x2 || shift > 0xd) {
57 } else if (shift < 0x8) {
59 result = (sample - (256 * shift)) << shift;
62 result = ((sample + ((256 * shift) + 1)) << shift) - 1;
69 * This is the dumbest implementation of all -- it simply looks at
70 * a fixed offset and if pack isn't there -- fails. We might want
71 * to have a fallback mechanism for complete search of missing packs.
73 static const uint8_t* dv_extract_pack(uint8_t* frame, enum dv_pack_type t)
79 offs = (80*6 + 80*16*3 + 3);
81 case dv_audio_control:
82 offs = (80*6 + 80*16*4 + 3);
84 case dv_video_control:
85 offs = (80*5 + 48 + 5);
91 return frame[offs] == t ? &frame[offs] : NULL;
95 * There's a couple of assumptions being made here:
96 * 1. By default we silence erroneous (0x8000/16bit 0x800/12bit) audio samples.
97 * We can pass them upwards when ffmpeg will be ready to deal with them.
98 * 2. We don't do software emphasis.
99 * 3. Audio is always returned as 16bit linear samples: 12bit nonlinear samples
100 * are converted into 16bit linear ones.
102 static int dv_extract_audio(uint8_t* frame, uint8_t* ppcm[4],
103 const DVprofile *sys)
105 int size, chan, i, j, d, of, smpls, freq, quant, half_ch;
107 const uint8_t* as_pack;
110 as_pack = dv_extract_pack(frame, dv_audio_source);
111 if (!as_pack) /* No audio ? */
114 smpls = as_pack[1] & 0x3f; /* samples in this frame - min. samples */
115 freq = (as_pack[4] >> 3) & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
116 quant = as_pack[4] & 0x07; /* 0 - 16bit linear, 1 - 12bit nonlinear */
119 return -1; /* Unsupported quantization */
121 size = (sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
122 half_ch = sys->difseg_size/2;
124 /* We work with 720p frames split in half, thus even frames have channels 0,1 and odd 2,3 */
125 ipcm = (sys->height == 720 && !(frame[1]&0x0C))?2:0;
128 /* for each DIF channel */
129 for (chan = 0; chan < sys->n_difchan; chan++) {
130 /* for each DIF segment */
131 for (i = 0; i < sys->difseg_size; i++) {
132 frame += 6 * 80; /* skip DIF segment header */
133 if (quant == 1 && i == half_ch) {
134 /* next stereo channel (12bit mode only) */
140 /* for each AV sequence */
141 for (j = 0; j < 9; j++) {
142 for (d = 8; d < 80; d += 2) {
143 if (quant == 0) { /* 16bit quantization */
144 of = sys->audio_shuffle[i][j] + (d - 8)/2 * sys->audio_stride;
148 pcm[of*2] = frame[d+1]; // FIXME: maybe we have to admit
149 pcm[of*2+1] = frame[d]; // that DV is a big-endian PCM
150 if (pcm[of*2+1] == 0x80 && pcm[of*2] == 0x00)
152 } else { /* 12bit quantization */
153 lc = ((uint16_t)frame[d] << 4) |
154 ((uint16_t)frame[d+2] >> 4);
155 rc = ((uint16_t)frame[d+1] << 4) |
156 ((uint16_t)frame[d+2] & 0x0f);
157 lc = (lc == 0x800 ? 0 : dv_audio_12to16(lc));
158 rc = (rc == 0x800 ? 0 : dv_audio_12to16(rc));
160 of = sys->audio_shuffle[i%half_ch][j] + (d - 8)/3 * sys->audio_stride;
164 pcm[of*2] = lc & 0xff; // FIXME: maybe we have to admit
165 pcm[of*2+1] = lc >> 8; // that DV is a big-endian PCM
166 of = sys->audio_shuffle[i%half_ch+half_ch][j] +
167 (d - 8)/3 * sys->audio_stride;
168 pcm[of*2] = rc & 0xff; // FIXME: maybe we have to admit
169 pcm[of*2+1] = rc >> 8; // that DV is a big-endian PCM
174 frame += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
178 /* next stereo channel (50Mbps and 100Mbps only) */
187 static int dv_extract_audio_info(DVDemuxContext* c, uint8_t* frame)
189 const uint8_t* as_pack;
190 int freq, stype, smpls, quant, i, ach;
192 as_pack = dv_extract_pack(frame, dv_audio_source);
193 if (!as_pack || !c->sys) { /* No audio ? */
198 smpls = as_pack[1] & 0x3f; /* samples in this frame - min. samples */
199 freq = (as_pack[4] >> 3) & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
200 stype = (as_pack[3] & 0x1f); /* 0 - 2CH, 2 - 4CH, 3 - 8CH */
201 quant = as_pack[4] & 0x07; /* 0 - 16bit linear, 1 - 12bit nonlinear */
203 /* note: ach counts PAIRS of channels (i.e. stereo channels) */
204 ach = ((int[4]){ 1, 0, 2, 4})[stype];
205 if (ach == 1 && quant && freq == 2)
208 /* Dynamic handling of the audio streams in DV */
209 for (i=0; i<ach; i++) {
211 c->ast[i] = av_new_stream(c->fctx, 0);
214 av_set_pts_info(c->ast[i], 64, 1, 30000);
215 c->ast[i]->codec->codec_type = CODEC_TYPE_AUDIO;
216 c->ast[i]->codec->codec_id = CODEC_ID_PCM_S16LE;
218 av_init_packet(&c->audio_pkt[i]);
219 c->audio_pkt[i].size = 0;
220 c->audio_pkt[i].data = c->audio_buf[i];
221 c->audio_pkt[i].stream_index = c->ast[i]->index;
222 c->audio_pkt[i].flags |= PKT_FLAG_KEY;
224 c->ast[i]->codec->sample_rate = dv_audio_frequency[freq];
225 c->ast[i]->codec->channels = 2;
226 c->ast[i]->codec->bit_rate = 2 * dv_audio_frequency[freq] * 16;
227 c->ast[i]->start_time = 0;
231 return (c->sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */;
234 static int dv_extract_video_info(DVDemuxContext *c, uint8_t* frame)
236 const uint8_t* vsc_pack;
237 AVCodecContext* avctx;
242 avctx = c->vst->codec;
244 av_set_pts_info(c->vst, 64, c->sys->time_base.num, c->sys->time_base.den);
245 avctx->time_base= c->sys->time_base;
247 avctx->width = c->sys->width;
248 avctx->height = c->sys->height;
250 avctx->pix_fmt = c->sys->pix_fmt;
252 /* finding out SAR is a little bit messy */
253 vsc_pack = dv_extract_pack(frame, dv_video_control);
254 apt = frame[4] & 0x07;
255 is16_9 = (vsc_pack && ((vsc_pack[2] & 0x07) == 0x02 ||
256 (!apt && (vsc_pack[2] & 0x07) == 0x07)));
257 c->vst->sample_aspect_ratio = c->sys->sar[is16_9];
258 avctx->bit_rate = av_rescale_q(c->sys->frame_size, (AVRational){8,1},
260 size = c->sys->frame_size;
266 * The following 3 functions constitute our interface to the world
269 DVDemuxContext* dv_init_demux(AVFormatContext *s)
273 c = av_mallocz(sizeof(DVDemuxContext));
277 c->vst = av_new_stream(s, 0);
285 memset(c->ast, 0, sizeof(c->ast));
290 c->vst->codec->codec_type = CODEC_TYPE_VIDEO;
291 c->vst->codec->codec_id = CODEC_ID_DVVIDEO;
292 c->vst->codec->bit_rate = 25000000;
293 c->vst->start_time = 0;
298 int dv_get_packet(DVDemuxContext *c, AVPacket *pkt)
303 for (i=0; i<c->ach; i++) {
304 if (c->ast[i] && c->audio_pkt[i].size) {
305 *pkt = c->audio_pkt[i];
306 c->audio_pkt[i].size = 0;
315 int dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,
316 uint8_t* buf, int buf_size)
319 uint8_t *ppcm[4] = {0};
321 if (buf_size < DV_PROFILE_BYTES ||
322 !(c->sys = dv_frame_profile(buf)) ||
323 buf_size < c->sys->frame_size) {
324 return -1; /* Broken frame, or not enough data */
327 /* Queueing audio packet */
328 /* FIXME: in case of no audio/bad audio we have to do something */
329 size = dv_extract_audio_info(c, buf);
330 for (i=0; i<c->ach; i++) {
331 c->audio_pkt[i].size = size;
332 c->audio_pkt[i].pts = c->abytes * 30000*8 / c->ast[i]->codec->bit_rate;
333 ppcm[i] = c->audio_buf[i];
335 dv_extract_audio(buf, ppcm, c->sys);
338 /* We work with 720p frames split in half, thus even frames have channels 0,1 and odd 2,3 */
339 if (c->sys->height == 720) {
341 c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
343 c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
346 /* Now it's time to return video packet */
347 size = dv_extract_video_info(c, buf);
351 pkt->flags |= PKT_FLAG_KEY;
352 pkt->stream_index = c->vst->id;
353 pkt->pts = c->frames;
360 static int64_t dv_frame_offset(AVFormatContext *s, DVDemuxContext *c,
361 int64_t timestamp, int flags)
363 // FIXME: sys may be wrong if last dv_read_packet() failed (buffer is junk)
364 const DVprofile* sys = dv_codec_profile(c->vst->codec);
366 int64_t size = url_fsize(s->pb);
367 int64_t max_offset = ((size-1) / sys->frame_size) * sys->frame_size;
369 offset = sys->frame_size * timestamp;
371 if (offset > max_offset) offset = max_offset;
372 else if (offset < 0) offset = 0;
377 void dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)
379 c->frames= frame_offset;
381 c->abytes= av_rescale_q(c->frames, c->sys->time_base,
382 (AVRational){8, c->ast[0]->codec->bit_rate});
383 c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
384 c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
387 /************************************************************
388 * Implementation of the easiest DV storage of all -- raw DV.
389 ************************************************************/
391 typedef struct RawDVContext {
392 DVDemuxContext* dv_demux;
393 uint8_t buf[DV_MAX_FRAME_SIZE];
396 static int dv_read_header(AVFormatContext *s,
397 AVFormatParameters *ap)
399 RawDVContext *c = s->priv_data;
401 c->dv_demux = dv_init_demux(s);
405 if (get_buffer(s->pb, c->buf, DV_PROFILE_BYTES) <= 0 ||
406 url_fseek(s->pb, -DV_PROFILE_BYTES, SEEK_CUR) < 0)
409 c->dv_demux->sys = dv_frame_profile(c->buf);
410 if (!c->dv_demux->sys) {
411 av_log(s, AV_LOG_ERROR, "Can't determine profile of DV input stream.\n");
415 s->bit_rate = av_rescale_q(c->dv_demux->sys->frame_size, (AVRational){8,1},
416 c->dv_demux->sys->time_base);
422 static int dv_read_packet(AVFormatContext *s, AVPacket *pkt)
425 RawDVContext *c = s->priv_data;
427 size = dv_get_packet(c->dv_demux, pkt);
430 size = c->dv_demux->sys->frame_size;
431 if (get_buffer(s->pb, c->buf, size) <= 0)
434 size = dv_produce_packet(c->dv_demux, pkt, c->buf, size);
440 static int dv_read_seek(AVFormatContext *s, int stream_index,
441 int64_t timestamp, int flags)
443 RawDVContext *r = s->priv_data;
444 DVDemuxContext *c = r->dv_demux;
445 int64_t offset= dv_frame_offset(s, c, timestamp, flags);
447 dv_offset_reset(c, offset / c->sys->frame_size);
449 offset = url_fseek(s->pb, offset, SEEK_SET);
450 return (offset < 0)?offset:0;
453 static int dv_read_close(AVFormatContext *s)
455 RawDVContext *c = s->priv_data;
456 av_free(c->dv_demux);
460 #ifdef CONFIG_DV_DEMUXER
461 AVInputFormat dv_demuxer = {
463 NULL_IF_CONFIG_SMALL("DV video format"),
464 sizeof(RawDVContext),
470 .extensions = "dv,dif",