3 * Copyright (c) 2004 The Libav Project
5 * first version by Francois Revol <revol@free.fr>
7 * This file is part of Libav.
9 * Libav is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
14 * Libav is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with Libav; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include "libavutil/attributes.h"
25 #include "libavutil/mathematics.h"
28 #include "libavutil/dict.h"
30 /* max bytes to crawl for trying to resync
31 * stupid streaming servers don't start at chunk boundaries...
33 #define NSV_MAX_RESYNC (500*1024)
34 #define NSV_MAX_RESYNC_TRIES 300
38 * (1) http://www.multimedia.cx/nsv-format.txt
39 * seems someone came to the same conclusions as me, and updated it:
40 * (2) http://www.stud.ktu.lt/~vitslav/nsv/nsv-format.txt
41 * http://www.stud.ktu.lt/~vitslav/nsv/
43 * (3) http://ultravox.aol.com/NSVFormat.rtf
45 * (S1) http://www.nullsoft.com/nsv/samples/
46 * http://www.nullsoft.com/nsv/samples/faster.nsv
47 * http://streamripper.sourceforge.net/openbb/read.php?TID=492&page=4
51 * notes on the header (Francois Revol):
53 * It is followed by strings, then a table, but nothing tells
54 * where the table begins according to (1). After checking faster.nsv,
55 * I believe NVSf[16-19] gives the size of the strings data
56 * (that is the offset of the data table after the header).
57 * After checking all samples from (S1) all confirms this.
59 * Then, about NSVf[12-15], faster.nsf has 179700. When viewing it in VLC,
60 * I noticed there was about 1 NVSs chunk/s, so I ran
61 * strings faster.nsv | grep NSVs | wc -l
62 * which gave me 180. That leads me to think that NSVf[12-15] might be the
63 * file length in milliseconds.
65 * for f in *.nsv; do HTIME="$(od -t x4 "$f" | head -1 | sed 's/.* //')"; echo "'$f' $((0x$HTIME))s = $((0x$HTIME/1000/60)):$((0x$HTIME/1000%60))"; done
66 * except for nsvtrailer (which doesn't have an NSVf header), it reports correct time.
68 * nsvtrailer.nsv (S1) does not have any NSVf header, only NSVs chunks,
69 * so the header seems to not be mandatory. (for streaming).
71 * index slice duration check (excepts nsvtrailer.nsv):
72 * for f in [^n]*.nsv; do
73 * DUR="$(avconv -i "$f" 2> /dev/null | grep 'NSVf duration' | cut -d ' ' -f 4)"
74 * IC="$(avconv -i "$f" 2> /dev/null | grep 'INDEX ENTRIES' | cut -d ' ' -f 2)"
75 * echo "duration $DUR, slite time $(($DUR/$IC))"
81 * - handle timestamps !!!
83 * - mime-type in probe()
89 uint32_t chunk_tag; /* 'NSVf' */
91 uint32_t file_size; /* max 4GB ??? no one learns anything it seems :^) */
92 uint32_t file_length; //unknown1; /* what about MSB of file_size ? */
93 uint32_t info_strings_size; /* size of the info strings */ //unknown2;
94 uint32_t table_entries;
95 uint32_t table_entries_used; /* the left ones should be -1 */
99 uint32_t chunk_tag; /* 'NSVs' */
100 uint32_t v4cc; /* or 'NONE' */
101 uint32_t a4cc; /* or 'NONE' */
102 uint16_t vwidth; /* assert(vwidth%16==0) */
103 uint16_t vheight; /* assert(vheight%16==0) */
104 uint8_t framerate; /* value = (framerate&0x80)?frtable[frameratex0x7f]:framerate */
108 struct nsv_avchunk_header {
109 uint8_t vchunk_size_lsb;
110 uint16_t vchunk_size_msb; /* value = (vchunk_size_msb << 4) | (vchunk_size_lsb >> 4) */
111 uint16_t achunk_size;
114 struct nsv_pcm_header {
115 uint8_t bits_per_sample;
116 uint8_t channel_count;
117 uint16_t sample_rate;
121 /* variation from avi.h */
122 /*typedef struct CodecTag {
129 #define T_NSVF MKTAG('N', 'S', 'V', 'f') /* file header */
130 #define T_NSVS MKTAG('N', 'S', 'V', 's') /* chunk header */
131 #define T_TOC2 MKTAG('T', 'O', 'C', '2') /* extra index marker */
132 #define T_NONE MKTAG('N', 'O', 'N', 'E') /* null a/v 4CC */
133 #define T_SUBT MKTAG('S', 'U', 'B', 'T') /* subtitle aux data */
134 #define T_ASYN MKTAG('A', 'S', 'Y', 'N') /* async a/v aux marker */
135 #define T_KEYF MKTAG('K', 'E', 'Y', 'F') /* video keyframe aux marker (addition) */
137 #define TB_NSVF MKBETAG('N', 'S', 'V', 'f')
138 #define TB_NSVS MKBETAG('N', 'S', 'V', 's')
140 /* hardcoded stream indexes */
141 #define NSV_ST_VIDEO 0
142 #define NSV_ST_AUDIO 1
143 #define NSV_ST_SUBT 2
156 typedef struct NSVStream {
157 int frame_offset; /* current frame (video) or byte (audio) counter
158 (used to compute the pts) */
161 int sample_size; /* audio only data */
164 int new_frame_offset; /* temporary storage (used during seek) */
165 int cum_len; /* temporary storage (used during seek) */
168 typedef struct NSVContext {
171 uint32_t *nsvs_file_offset;
173 enum NSVStatus state;
174 AVPacket ahead[2]; /* [v, a] if .data is !NULL there is something */
178 uint16_t vwidth, vheight;
180 AVRational framerate;
181 uint32_t *nsvs_timestamps;
184 static const AVCodecTag nsv_codec_video_tags[] = {
185 { AV_CODEC_ID_VP3, MKTAG('V', 'P', '3', ' ') },
186 { AV_CODEC_ID_VP3, MKTAG('V', 'P', '3', '0') },
187 { AV_CODEC_ID_VP3, MKTAG('V', 'P', '3', '1') },
188 { AV_CODEC_ID_VP5, MKTAG('V', 'P', '5', ' ') },
189 { AV_CODEC_ID_VP5, MKTAG('V', 'P', '5', '0') },
190 { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', ' ') },
191 { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', '0') },
192 { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', '1') },
193 { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', '2') },
195 { AV_CODEC_ID_VP4, MKTAG('V', 'P', '4', ' ') },
196 { AV_CODEC_ID_VP4, MKTAG('V', 'P', '4', '0') },
198 { AV_CODEC_ID_MPEG4, MKTAG('X', 'V', 'I', 'D') }, /* cf sample xvid decoder from nsv_codec_sdk.zip */
199 { AV_CODEC_ID_RAWVIDEO, MKTAG('R', 'G', 'B', '3') },
200 { AV_CODEC_ID_NONE, 0 },
203 static const AVCodecTag nsv_codec_audio_tags[] = {
204 { AV_CODEC_ID_MP3, MKTAG('M', 'P', '3', ' ') },
205 { AV_CODEC_ID_AAC, MKTAG('A', 'A', 'C', ' ') },
206 { AV_CODEC_ID_AAC, MKTAG('A', 'A', 'C', 'P') },
207 { AV_CODEC_ID_SPEEX, MKTAG('S', 'P', 'X', ' ') },
208 { AV_CODEC_ID_PCM_U16LE, MKTAG('P', 'C', 'M', ' ') },
209 { AV_CODEC_ID_NONE, 0 },
212 //static int nsv_load_index(AVFormatContext *s);
213 static int nsv_read_chunk(AVFormatContext *s, int fill_header);
215 /* try to find something we recognize, and set the state accordingly */
216 static int nsv_resync(AVFormatContext *s)
218 NSVContext *nsv = s->priv_data;
219 AVIOContext *pb = s->pb;
223 for (i = 0; i < NSV_MAX_RESYNC; i++) {
224 if (pb->eof_reached) {
225 av_log(s, AV_LOG_TRACE, "NSV EOF\n");
226 nsv->state = NSV_UNSYNC;
232 av_log(s, AV_LOG_TRACE, "NSV resync: [%d] = %02"PRIx32"\n", i, v & 0x0FF);
235 if ((v & 0x0000ffff) == 0xefbe) { /* BEEF */
236 av_log(s, AV_LOG_TRACE, "NSV resynced on BEEF after %d bytes\n", i+1);
237 nsv->state = NSV_FOUND_BEEF;
240 /* we read as big-endian, thus the MK*BE* */
241 if (v == TB_NSVF) { /* NSVf */
242 av_log(s, AV_LOG_TRACE, "NSV resynced on NSVf after %d bytes\n", i+1);
243 nsv->state = NSV_FOUND_NSVF;
246 if (v == MKBETAG('N', 'S', 'V', 's')) { /* NSVs */
247 av_log(s, AV_LOG_TRACE, "NSV resynced on NSVs after %d bytes\n", i+1);
248 nsv->state = NSV_FOUND_NSVS;
253 av_log(s, AV_LOG_TRACE, "NSV sync lost\n");
257 static int nsv_parse_NSVf_header(AVFormatContext *s)
259 NSVContext *nsv = s->priv_data;
260 AVIOContext *pb = s->pb;
261 unsigned int av_unused file_size;
266 int table_entries_used;
268 nsv->state = NSV_UNSYNC; /* in case we fail */
270 size = avio_rl32(pb);
273 nsv->NSVf_end = size;
275 file_size = (uint32_t)avio_rl32(pb);
276 av_log(s, AV_LOG_TRACE, "NSV NSVf chunk_size %u\n", size);
277 av_log(s, AV_LOG_TRACE, "NSV NSVf file_size %u\n", file_size);
279 nsv->duration = duration = avio_rl32(pb); /* in ms */
280 av_log(s, AV_LOG_TRACE, "NSV NSVf duration %"PRId64" ms\n", duration);
281 // XXX: store it in AVStreams
283 strings_size = avio_rl32(pb);
284 table_entries = avio_rl32(pb);
285 table_entries_used = avio_rl32(pb);
286 av_log(s, AV_LOG_TRACE, "NSV NSVf info-strings size: %d, table entries: %d, bis %d\n",
287 strings_size, table_entries, table_entries_used);
291 av_log(s, AV_LOG_TRACE, "NSV got header; filepos %"PRId64"\n", avio_tell(pb));
293 if (strings_size > 0) {
294 char *strings; /* last byte will be '\0' to play safe with str*() */
299 p = strings = av_mallocz((size_t)strings_size + 1);
301 return AVERROR(ENOMEM);
302 endp = strings + strings_size;
303 avio_read(pb, strings, strings_size);
306 p++; /* strip out spaces */
311 if (!p || p >= endp-2)
316 p = strchr(p, quote);
320 av_log(s, AV_LOG_TRACE, "NSV NSVf INFO: %s='%s'\n", token, value);
321 av_dict_set(&s->metadata, token, value, 0);
328 av_log(s, AV_LOG_TRACE, "NSV got infos; filepos %"PRId64"\n", avio_tell(pb));
330 if (table_entries_used > 0) {
332 nsv->index_entries = table_entries_used;
333 if((unsigned)table_entries_used >= UINT_MAX / sizeof(uint32_t))
335 nsv->nsvs_file_offset = av_malloc((unsigned)table_entries_used * sizeof(uint32_t));
336 if (!nsv->nsvs_file_offset)
337 return AVERROR(ENOMEM);
339 for(i=0;i<table_entries_used;i++)
340 nsv->nsvs_file_offset[i] = avio_rl32(pb) + size;
342 if(table_entries > table_entries_used &&
343 avio_rl32(pb) == MKTAG('T','O','C','2')) {
344 nsv->nsvs_timestamps = av_malloc((unsigned)table_entries_used*sizeof(uint32_t));
345 if (!nsv->nsvs_timestamps)
346 return AVERROR(ENOMEM);
347 for(i=0;i<table_entries_used;i++) {
348 nsv->nsvs_timestamps[i] = avio_rl32(pb);
353 av_log(s, AV_LOG_TRACE, "NSV got index; filepos %"PRId64"\n", avio_tell(pb));
355 avio_seek(pb, nsv->base_offset + size, SEEK_SET); /* required for dumbdriving-271.nsv (2 extra bytes) */
359 nsv->state = NSV_HAS_READ_NSVF;
363 static int nsv_parse_NSVs_header(AVFormatContext *s)
365 NSVContext *nsv = s->priv_data;
366 AVIOContext *pb = s->pb;
368 uint16_t vwidth, vheight;
369 AVRational framerate;
374 vtag = avio_rl32(pb);
375 atag = avio_rl32(pb);
376 vwidth = avio_rl16(pb);
377 vheight = avio_rl16(pb);
380 av_log(s, AV_LOG_TRACE, "NSV NSVs framerate code %2x\n", i);
381 if(i&0x80) { /* odd way of giving native framerates from docs */
383 if(t<16) framerate = (AVRational){1, t+1};
384 else framerate = (AVRational){t-15, 1};
387 framerate.num *= 1000;
388 framerate.den *= 1001;
391 if((i&3)==3) framerate.num *= 24;
392 else if((i&3)==2) framerate.num *= 25;
393 else framerate.num *= 30;
396 framerate= (AVRational){i, 1};
398 nsv->avsync = avio_rl16(pb);
399 nsv->framerate = framerate;
401 av_log(s, AV_LOG_TRACE, "NSV NSVs vsize %"PRIu16"x%"PRIu16"\n",
404 /* XXX change to ap != NULL ? */
405 if (s->nb_streams == 0) { /* streams not yet published, let's do that */
408 nsv->vwidth = vwidth;
409 nsv->vheight = vwidth;
410 if (vtag != T_NONE) {
412 st = avformat_new_stream(s, NULL);
416 st->id = NSV_ST_VIDEO;
417 nst = av_mallocz(sizeof(NSVStream));
421 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
422 st->codecpar->codec_tag = vtag;
423 st->codecpar->codec_id = ff_codec_get_id(nsv_codec_video_tags, vtag);
424 st->codecpar->width = vwidth;
425 st->codecpar->height = vheight;
426 st->codecpar->bits_per_coded_sample = 24; /* depth XXX */
428 avpriv_set_pts_info(st, 64, framerate.den, framerate.num);
430 st->duration = av_rescale(nsv->duration, framerate.num, 1000*framerate.den);
432 for(i=0;i<nsv->index_entries;i++) {
433 if(nsv->nsvs_timestamps) {
434 av_add_index_entry(st, nsv->nsvs_file_offset[i], nsv->nsvs_timestamps[i],
435 0, 0, AVINDEX_KEYFRAME);
437 int64_t ts = av_rescale(i*nsv->duration/nsv->index_entries, framerate.num, 1000*framerate.den);
438 av_add_index_entry(st, nsv->nsvs_file_offset[i], ts, 0, 0, AVINDEX_KEYFRAME);
442 if (atag != T_NONE) {
443 st = avformat_new_stream(s, NULL);
447 st->id = NSV_ST_AUDIO;
448 nst = av_mallocz(sizeof(NSVStream));
452 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
453 st->codecpar->codec_tag = atag;
454 st->codecpar->codec_id = ff_codec_get_id(nsv_codec_audio_tags, atag);
456 st->need_parsing = AVSTREAM_PARSE_FULL; /* for PCM we will read a chunk later and put correct info */
458 /* set timebase to common denominator of ms and framerate */
459 avpriv_set_pts_info(st, 64, 1, framerate.num*1000);
461 st->duration = (int64_t)nsv->duration * framerate.num;
464 if (nsv->vtag != vtag || nsv->atag != atag || nsv->vwidth != vwidth || nsv->vheight != vwidth) {
465 av_log(s, AV_LOG_TRACE, "NSV NSVs header values differ from the first one!!!\n");
470 nsv->state = NSV_HAS_READ_NSVS;
474 nsv->state = NSV_UNSYNC;
478 static int nsv_read_header(AVFormatContext *s)
480 NSVContext *nsv = s->priv_data;
483 nsv->state = NSV_UNSYNC;
484 nsv->ahead[0].data = nsv->ahead[1].data = NULL;
486 for (i = 0; i < NSV_MAX_RESYNC_TRIES; i++) {
487 if (nsv_resync(s) < 0)
489 if (nsv->state == NSV_FOUND_NSVF) {
490 err = nsv_parse_NSVf_header(s);
494 /* we need the first NSVs also... */
495 if (nsv->state == NSV_FOUND_NSVS) {
496 err = nsv_parse_NSVs_header(s);
499 break; /* we just want the first one */
502 if (s->nb_streams < 1) /* no luck so far */
504 /* now read the first chunk, so we can attempt to decode more info */
505 err = nsv_read_chunk(s, 1);
507 av_log(s, AV_LOG_TRACE, "parsed header\n");
511 static int nsv_read_chunk(AVFormatContext *s, int fill_header)
513 NSVContext *nsv = s->priv_data;
514 AVIOContext *pb = s->pb;
515 AVStream *st[2] = {NULL, NULL};
519 uint8_t auxcount; /* number of aux metadata, also 4 bits of vsize */
524 if (nsv->ahead[0].data || nsv->ahead[1].data)
525 return 0; //-1; /* hey! eat what you've in your plate first! */
531 for (i = 0; i < NSV_MAX_RESYNC_TRIES && nsv->state < NSV_FOUND_NSVS && !err; i++)
535 if (nsv->state == NSV_FOUND_NSVS)
536 err = nsv_parse_NSVs_header(s);
539 if (nsv->state != NSV_HAS_READ_NSVS && nsv->state != NSV_FOUND_BEEF)
542 auxcount = avio_r8(pb);
543 vsize = avio_rl16(pb);
544 asize = avio_rl16(pb);
545 vsize = (vsize << 4) | (auxcount >> 4);
547 av_log(s, AV_LOG_TRACE, "NSV CHUNK %"PRIu8" aux, %"PRIu32" bytes video, %"PRIu16" bytes audio\n",
548 auxcount, vsize, asize);
550 for (i = 0; i < auxcount; i++) {
551 uint32_t av_unused auxtag;
552 auxsize = avio_rl16(pb);
553 auxtag = avio_rl32(pb);
554 avio_skip(pb, auxsize);
555 vsize -= auxsize + sizeof(uint16_t) + sizeof(uint32_t); /* that's becoming brain-dead */
560 if (!vsize && !asize) {
561 nsv->state = NSV_UNSYNC;
562 goto null_chunk_retry;
565 /* map back streams to v,a */
566 if (s->nb_streams > 0)
567 st[s->streams[0]->id] = s->streams[0];
568 if (s->nb_streams > 1)
569 st[s->streams[1]->id] = s->streams[1];
571 if (vsize && st[NSV_ST_VIDEO]) {
572 nst = st[NSV_ST_VIDEO]->priv_data;
573 pkt = &nsv->ahead[NSV_ST_VIDEO];
574 av_get_packet(pb, pkt, vsize);
575 pkt->stream_index = st[NSV_ST_VIDEO]->index;//NSV_ST_VIDEO;
576 pkt->dts = nst->frame_offset;
577 pkt->flags |= nsv->state == NSV_HAS_READ_NSVS ? AV_PKT_FLAG_KEY : 0; /* keyframe only likely on a sync frame */
578 for (i = 0; i < FFMIN(8, vsize); i++)
579 av_log(s, AV_LOG_TRACE, "NSV video: [%d] = %02"PRIx8"\n",
583 ((NSVStream*)st[NSV_ST_VIDEO]->priv_data)->frame_offset++;
585 if (asize && st[NSV_ST_AUDIO]) {
586 nst = st[NSV_ST_AUDIO]->priv_data;
587 pkt = &nsv->ahead[NSV_ST_AUDIO];
588 /* read raw audio specific header on the first audio chunk... */
589 /* on ALL audio chunks ?? seems so! */
590 if (asize && st[NSV_ST_AUDIO]->codecpar->codec_tag == MKTAG('P', 'C', 'M', ' ')/* && fill_header*/) {
595 channels = avio_r8(pb);
596 samplerate = avio_rl16(pb);
597 if (!channels || !samplerate)
598 return AVERROR_INVALIDDATA;
600 av_log(s, AV_LOG_TRACE, "NSV RAWAUDIO: bps %"PRIu8", nchan %"PRIu8", srate %"PRIu16"\n",
601 bps, channels, samplerate);
603 st[NSV_ST_AUDIO]->need_parsing = AVSTREAM_PARSE_NONE; /* we know everything */
605 av_log(s, AV_LOG_TRACE, "NSV AUDIO bit/sample != 16 (%"PRIu8")!!!\n", bps);
607 bps /= channels; // ???
609 st[NSV_ST_AUDIO]->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
610 samplerate /= 4;/* UGH ??? XXX */
612 st[NSV_ST_AUDIO]->codecpar->channels = channels;
613 st[NSV_ST_AUDIO]->codecpar->sample_rate = samplerate;
614 av_log(s, AV_LOG_TRACE, "NSV RAWAUDIO: bps %"PRIu8", nchan %"PRIu8", srate %"PRIu16"\n",
615 bps, channels, samplerate);
618 av_get_packet(pb, pkt, asize);
619 pkt->stream_index = st[NSV_ST_AUDIO]->index;//NSV_ST_AUDIO;
620 pkt->flags |= nsv->state == NSV_HAS_READ_NSVS ? AV_PKT_FLAG_KEY : 0; /* keyframe only likely on a sync frame */
621 if( nsv->state == NSV_HAS_READ_NSVS && st[NSV_ST_VIDEO] ) {
622 /* on a nsvs frame we have new information on a/v sync */
623 pkt->dts = (((NSVStream*)st[NSV_ST_VIDEO]->priv_data)->frame_offset-1);
624 pkt->dts *= (int64_t)1000 * nsv->framerate.den;
625 pkt->dts += (int64_t)nsv->avsync * nsv->framerate.num;
626 av_log(s, AV_LOG_TRACE, "NSV AUDIO: sync:%"PRId16", dts:%"PRId64,
627 nsv->avsync, pkt->dts);
632 nsv->state = NSV_UNSYNC;
637 static int nsv_read_packet(AVFormatContext *s, AVPacket *pkt)
639 NSVContext *nsv = s->priv_data;
642 /* in case we don't already have something to eat ... */
643 if (!nsv->ahead[0].data && !nsv->ahead[1].data)
644 err = nsv_read_chunk(s, 0);
648 /* now pick one of the plates */
649 for (i = 0; i < 2; i++) {
650 if (nsv->ahead[i].data) {
651 /* avoid the cost of new_packet + memcpy(->data) */
652 memcpy(pkt, &nsv->ahead[i], sizeof(AVPacket));
653 nsv->ahead[i].data = NULL; /* we ate that one */
658 /* this restaurant is not provisioned :^] */
662 static int nsv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
664 NSVContext *nsv = s->priv_data;
665 AVStream *st = s->streams[stream_index];
666 NSVStream *nst = st->priv_data;
669 index = av_index_search_timestamp(st, timestamp, flags);
673 if (avio_seek(s->pb, st->index_entries[index].pos, SEEK_SET) < 0)
676 nst->frame_offset = st->index_entries[index].timestamp;
677 nsv->state = NSV_UNSYNC;
681 static int nsv_read_close(AVFormatContext *s)
683 NSVContext *nsv = s->priv_data;
685 av_freep(&nsv->nsvs_file_offset);
686 av_freep(&nsv->nsvs_timestamps);
687 if (nsv->ahead[0].data)
688 av_packet_unref(&nsv->ahead[0]);
689 if (nsv->ahead[1].data)
690 av_packet_unref(&nsv->ahead[1]);
694 static int nsv_probe(AVProbeData *p)
698 int vsize, asize, auxcount;
700 av_log(NULL, AV_LOG_TRACE, "nsv_probe(), buf_size %d\n", p->buf_size);
701 /* check file header */
702 /* streamed files might not have any header */
703 if (p->buf[0] == 'N' && p->buf[1] == 'S' &&
704 p->buf[2] == 'V' && (p->buf[3] == 'f' || p->buf[3] == 's'))
705 return AVPROBE_SCORE_MAX;
706 /* XXX: do streamed files always start at chunk boundary ?? */
707 /* or do we need to search NSVs in the byte stream ? */
708 /* seems the servers don't bother starting clean chunks... */
709 /* sometimes even the first header is at 9KB or something :^) */
710 for (i = 1; i < p->buf_size - 3; i++) {
711 if (p->buf[i+0] == 'N' && p->buf[i+1] == 'S' &&
712 p->buf[i+2] == 'V' && p->buf[i+3] == 's') {
713 score = AVPROBE_SCORE_MAX/5;
714 /* Get the chunk size and check if at the end we are getting 0xBEEF */
715 auxcount = p->buf[i+19];
716 vsize = p->buf[i+20] | p->buf[i+21] << 8;
717 asize = p->buf[i+22] | p->buf[i+23] << 8;
718 vsize = (vsize << 4) | (auxcount >> 4);
719 if ((asize + vsize + i + 23) < p->buf_size - 2) {
720 if (p->buf[i+23+asize+vsize+1] == 0xEF &&
721 p->buf[i+23+asize+vsize+2] == 0xBE)
722 return AVPROBE_SCORE_MAX-20;
726 /* so we'll have more luck on extension... */
727 if (av_match_ext(p->filename, "nsv"))
728 return AVPROBE_SCORE_EXTENSION;
729 /* FIXME: add mime-type check */
733 AVInputFormat ff_nsv_demuxer = {
735 .long_name = NULL_IF_CONFIG_SMALL("Nullsoft Streaming Video"),
736 .priv_data_size = sizeof(NSVContext),
737 .read_probe = nsv_probe,
738 .read_header = nsv_read_header,
739 .read_packet = nsv_read_packet,
740 .read_close = nsv_read_close,
741 .read_seek = nsv_read_seek,