3 * Copyright (c) 2004 The FFmpeg Project
5 * first version by Francois Revol <revol@free.fr>
7 * This file is part of FFmpeg.
9 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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"
29 #include "libavutil/intreadwrite.h"
31 /* max bytes to crawl for trying to resync
32 * stupid streaming servers don't start at chunk boundaries...
34 #define NSV_MAX_RESYNC (500*1024)
35 #define NSV_MAX_RESYNC_TRIES 300
39 * (1) http://www.multimedia.cx/nsv-format.txt
40 * seems someone came to the same conclusions as me, and updated it:
41 * (2) http://www.stud.ktu.lt/~vitslav/nsv/nsv-format.txt
42 * http://www.stud.ktu.lt/~vitslav/nsv/
44 * (3) http://ultravox.aol.com/NSVFormat.rtf
46 * (S1) http://www.nullsoft.com/nsv/samples/
47 * http://www.nullsoft.com/nsv/samples/faster.nsv
48 * http://streamripper.sourceforge.net/openbb/read.php?TID=492&page=4
52 * notes on the header (Francois Revol):
54 * It is followed by strings, then a table, but nothing tells
55 * where the table begins according to (1). After checking faster.nsv,
56 * I believe NVSf[16-19] gives the size of the strings data
57 * (that is the offset of the data table after the header).
58 * After checking all samples from (S1) all confirms this.
60 * Then, about NSVf[12-15], faster.nsf has 179700. When viewing it in VLC,
61 * I noticed there was about 1 NVSs chunk/s, so I ran
62 * strings faster.nsv | grep NSVs | wc -l
63 * which gave me 180. That leads me to think that NSVf[12-15] might be the
64 * file length in milliseconds.
66 * 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
67 * except for nsvtrailer (which doesn't have an NSVf header), it reports correct time.
69 * nsvtrailer.nsv (S1) does not have any NSVf header, only NSVs chunks,
70 * so the header seems to not be mandatory. (for streaming).
72 * index slice duration check (excepts nsvtrailer.nsv):
73 * for f in [^n]*.nsv; do DUR="$(ffmpeg -i "$f" 2>/dev/null | grep 'NSVf duration' | cut -d ' ' -f 4)"; IC="$(ffmpeg -i "$f" 2>/dev/null | grep 'INDEX ENTRIES' | cut -d ' ' -f 2)"; echo "duration $DUR, slite time $(($DUR/$IC))"; done
78 * - handle timestamps !!!
80 * - mime-type in probe()
86 uint32_t chunk_tag; /* 'NSVf' */
88 uint32_t file_size; /* max 4GB ??? no one learns anything it seems :^) */
89 uint32_t file_length; //unknown1; /* what about MSB of file_size ? */
90 uint32_t info_strings_size; /* size of the info strings */ //unknown2;
91 uint32_t table_entries;
92 uint32_t table_entries_used; /* the left ones should be -1 */
96 uint32_t chunk_tag; /* 'NSVs' */
97 uint32_t v4cc; /* or 'NONE' */
98 uint32_t a4cc; /* or 'NONE' */
99 uint16_t vwidth; /* av_assert0(vwidth%16==0) */
100 uint16_t vheight; /* av_assert0(vheight%16==0) */
101 uint8_t framerate; /* value = (framerate&0x80)?frtable[frameratex0x7f]:framerate */
105 struct nsv_avchunk_header {
106 uint8_t vchunk_size_lsb;
107 uint16_t vchunk_size_msb; /* value = (vchunk_size_msb << 4) | (vchunk_size_lsb >> 4) */
108 uint16_t achunk_size;
111 struct nsv_pcm_header {
112 uint8_t bits_per_sample;
113 uint8_t channel_count;
114 uint16_t sample_rate;
118 /* variation from avi.h */
119 /*typedef struct CodecTag {
126 #define T_NSVF MKTAG('N', 'S', 'V', 'f') /* file header */
127 #define T_NSVS MKTAG('N', 'S', 'V', 's') /* chunk header */
128 #define T_TOC2 MKTAG('T', 'O', 'C', '2') /* extra index marker */
129 #define T_NONE MKTAG('N', 'O', 'N', 'E') /* null a/v 4CC */
130 #define T_SUBT MKTAG('S', 'U', 'B', 'T') /* subtitle aux data */
131 #define T_ASYN MKTAG('A', 'S', 'Y', 'N') /* async a/v aux marker */
132 #define T_KEYF MKTAG('K', 'E', 'Y', 'F') /* video keyframe aux marker (addition) */
134 #define TB_NSVF MKBETAG('N', 'S', 'V', 'f')
135 #define TB_NSVS MKBETAG('N', 'S', 'V', 's')
137 /* hardcoded stream indexes */
138 #define NSV_ST_VIDEO 0
139 #define NSV_ST_AUDIO 1
140 #define NSV_ST_SUBT 2
153 typedef struct NSVStream {
154 int frame_offset; /* current frame (video) or byte (audio) counter
155 (used to compute the pts) */
158 int sample_size; /* audio only data */
161 int new_frame_offset; /* temporary storage (used during seek) */
162 int cum_len; /* temporary storage (used during seek) */
165 typedef struct NSVContext {
168 uint32_t *nsvs_file_offset;
170 enum NSVStatus state;
171 AVPacket ahead[2]; /* [v, a] if .data is !NULL there is something */
175 uint16_t vwidth, vheight;
177 AVRational framerate;
178 uint32_t *nsvs_timestamps;
181 static const AVCodecTag nsv_codec_video_tags[] = {
182 { AV_CODEC_ID_VP3, MKTAG('V', 'P', '3', ' ') },
183 { AV_CODEC_ID_VP3, MKTAG('V', 'P', '3', '0') },
184 { AV_CODEC_ID_VP3, MKTAG('V', 'P', '3', '1') },
185 { AV_CODEC_ID_VP5, MKTAG('V', 'P', '5', ' ') },
186 { AV_CODEC_ID_VP5, MKTAG('V', 'P', '5', '0') },
187 { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', ' ') },
188 { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', '0') },
189 { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', '1') },
190 { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', '2') },
191 { AV_CODEC_ID_VP8, MKTAG('V', 'P', '8', '0') },
193 { AV_CODEC_ID_VP4, MKTAG('V', 'P', '4', ' ') },
194 { AV_CODEC_ID_VP4, MKTAG('V', 'P', '4', '0') },
196 { AV_CODEC_ID_MPEG4, MKTAG('X', 'V', 'I', 'D') }, /* cf sample xvid decoder from nsv_codec_sdk.zip */
197 { AV_CODEC_ID_RAWVIDEO, MKTAG('R', 'G', 'B', '3') },
198 { AV_CODEC_ID_NONE, 0 },
201 static const AVCodecTag nsv_codec_audio_tags[] = {
202 { AV_CODEC_ID_MP3, MKTAG('M', 'P', '3', ' ') },
203 { AV_CODEC_ID_AAC, MKTAG('A', 'A', 'C', ' ') },
204 { AV_CODEC_ID_AAC, MKTAG('A', 'A', 'C', 'P') },
205 { AV_CODEC_ID_AAC, MKTAG('V', 'L', 'B', ' ') },
206 { AV_CODEC_ID_SPEEX, MKTAG('S', 'P', 'X', ' ') },
207 { AV_CODEC_ID_PCM_U16LE, MKTAG('P', 'C', 'M', ' ') },
208 { AV_CODEC_ID_NONE, 0 },
211 //static int nsv_load_index(AVFormatContext *s);
212 static int nsv_read_chunk(AVFormatContext *s, int fill_header);
214 /* try to find something we recognize, and set the state accordingly */
215 static int nsv_resync(AVFormatContext *s)
217 NSVContext *nsv = s->priv_data;
218 AVIOContext *pb = s->pb;
222 for (i = 0; i < NSV_MAX_RESYNC; i++) {
224 av_log(s, AV_LOG_TRACE, "NSV EOF\n");
225 nsv->state = NSV_UNSYNC;
231 av_log(s, AV_LOG_TRACE, "NSV resync: [%d] = %02x\n", i, v & 0x0FF);
234 if ((v & 0x0000ffff) == 0xefbe) { /* BEEF */
235 av_log(s, AV_LOG_TRACE, "NSV resynced on BEEF after %d bytes\n", i+1);
236 nsv->state = NSV_FOUND_BEEF;
239 /* we read as big-endian, thus the MK*BE* */
240 if (v == TB_NSVF) { /* NSVf */
241 av_log(s, AV_LOG_TRACE, "NSV resynced on NSVf after %d bytes\n", i+1);
242 nsv->state = NSV_FOUND_NSVF;
245 if (v == MKBETAG('N', 'S', 'V', 's')) { /* NSVs */
246 av_log(s, AV_LOG_TRACE, "NSV resynced on NSVs after %d bytes\n", i+1);
247 nsv->state = NSV_FOUND_NSVS;
252 av_log(s, AV_LOG_TRACE, "NSV sync lost\n");
256 static int nsv_parse_NSVf_header(AVFormatContext *s)
258 NSVContext *nsv = s->priv_data;
259 AVIOContext *pb = s->pb;
260 unsigned int av_unused file_size;
265 int table_entries_used;
267 nsv->state = NSV_UNSYNC; /* in case we fail */
269 size = avio_rl32(pb);
272 nsv->NSVf_end = size;
274 file_size = (uint32_t)avio_rl32(pb);
275 av_log(s, AV_LOG_TRACE, "NSV NSVf chunk_size %u\n", size);
276 av_log(s, AV_LOG_TRACE, "NSV NSVf file_size %u\n", file_size);
278 nsv->duration = duration = avio_rl32(pb); /* in ms */
279 av_log(s, AV_LOG_TRACE, "NSV NSVf duration %"PRId64" ms\n", duration);
280 // XXX: store it in AVStreams
282 strings_size = avio_rl32(pb);
283 table_entries = avio_rl32(pb);
284 table_entries_used = avio_rl32(pb);
285 av_log(s, AV_LOG_TRACE, "NSV NSVf info-strings size: %d, table entries: %d, bis %d\n",
286 strings_size, table_entries, table_entries_used);
290 av_log(s, AV_LOG_TRACE, "NSV got header; filepos %"PRId64"\n", avio_tell(pb));
292 if (strings_size > 0) {
293 char *strings; /* last byte will be '\0' to play safe with str*() */
298 p = strings = av_mallocz((size_t)strings_size + 1);
300 return AVERROR(ENOMEM);
301 endp = strings + strings_size;
302 avio_read(pb, strings, strings_size);
305 p++; /* strip out spaces */
310 if (!p || p >= endp-2)
315 p = strchr(p, quote);
319 av_log(s, AV_LOG_TRACE, "NSV NSVf INFO: %s='%s'\n", token, value);
320 av_dict_set(&s->metadata, token, value, 0);
327 av_log(s, AV_LOG_TRACE, "NSV got infos; filepos %"PRId64"\n", avio_tell(pb));
329 if (table_entries_used > 0) {
331 nsv->index_entries = table_entries_used;
332 if((unsigned)table_entries_used >= UINT_MAX / sizeof(uint32_t))
334 nsv->nsvs_file_offset = av_malloc_array((unsigned)table_entries_used, sizeof(uint32_t));
335 if (!nsv->nsvs_file_offset)
336 return AVERROR(ENOMEM);
338 for(i=0;i<table_entries_used;i++)
339 nsv->nsvs_file_offset[i] = avio_rl32(pb) + size;
341 if(table_entries > table_entries_used &&
342 avio_rl32(pb) == MKTAG('T','O','C','2')) {
343 nsv->nsvs_timestamps = av_malloc_array((unsigned)table_entries_used, sizeof(uint32_t));
344 if (!nsv->nsvs_timestamps)
345 return AVERROR(ENOMEM);
346 for(i=0;i<table_entries_used;i++) {
347 nsv->nsvs_timestamps[i] = avio_rl32(pb);
352 av_log(s, AV_LOG_TRACE, "NSV got index; filepos %"PRId64"\n", avio_tell(pb));
354 avio_seek(pb, nsv->base_offset + size, SEEK_SET); /* required for dumbdriving-271.nsv (2 extra bytes) */
358 nsv->state = NSV_HAS_READ_NSVF;
362 static int nsv_parse_NSVs_header(AVFormatContext *s)
364 NSVContext *nsv = s->priv_data;
365 AVIOContext *pb = s->pb;
367 uint16_t vwidth, vheight;
368 AVRational framerate;
373 vtag = avio_rl32(pb);
374 atag = avio_rl32(pb);
375 vwidth = avio_rl16(pb);
376 vheight = avio_rl16(pb);
379 av_log(s, AV_LOG_TRACE, "NSV NSVs framerate code %2x\n", i);
380 if(i&0x80) { /* odd way of giving native framerates from docs */
382 if(t<16) framerate = (AVRational){1, t+1};
383 else framerate = (AVRational){t-15, 1};
386 framerate.num *= 1000;
387 framerate.den *= 1001;
390 if((i&3)==3) framerate.num *= 24;
391 else if((i&3)==2) framerate.num *= 25;
392 else framerate.num *= 30;
395 framerate= (AVRational){i, 1};
397 nsv->avsync = avio_rl16(pb);
398 nsv->framerate = framerate;
400 av_log(s, AV_LOG_TRACE, "NSV NSVs vsize %dx%d\n", vwidth, vheight);
402 /* XXX change to ap != NULL ? */
403 if (s->nb_streams == 0) { /* streams not yet published, let's do that */
406 nsv->vwidth = vwidth;
407 nsv->vheight = vwidth;
408 if (vtag != T_NONE) {
410 st = avformat_new_stream(s, NULL);
414 st->id = NSV_ST_VIDEO;
415 nst = av_mallocz(sizeof(NSVStream));
419 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
420 st->codecpar->codec_tag = vtag;
421 st->codecpar->codec_id = ff_codec_get_id(nsv_codec_video_tags, vtag);
422 st->codecpar->width = vwidth;
423 st->codecpar->height = vheight;
424 st->codecpar->bits_per_coded_sample = 24; /* depth XXX */
426 avpriv_set_pts_info(st, 64, framerate.den, framerate.num);
428 st->duration = av_rescale(nsv->duration, framerate.num, 1000*framerate.den);
430 for(i=0;i<nsv->index_entries;i++) {
431 if(nsv->nsvs_timestamps) {
432 av_add_index_entry(st, nsv->nsvs_file_offset[i], nsv->nsvs_timestamps[i],
433 0, 0, AVINDEX_KEYFRAME);
435 int64_t ts = av_rescale(i*nsv->duration/nsv->index_entries, framerate.num, 1000*framerate.den);
436 av_add_index_entry(st, nsv->nsvs_file_offset[i], ts, 0, 0, AVINDEX_KEYFRAME);
440 if (atag != T_NONE) {
441 st = avformat_new_stream(s, NULL);
445 st->id = NSV_ST_AUDIO;
446 nst = av_mallocz(sizeof(NSVStream));
450 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
451 st->codecpar->codec_tag = atag;
452 st->codecpar->codec_id = ff_codec_get_id(nsv_codec_audio_tags, atag);
454 st->need_parsing = AVSTREAM_PARSE_FULL; /* for PCM we will read a chunk later and put correct info */
456 /* set timebase to common denominator of ms and framerate */
457 avpriv_set_pts_info(st, 64, 1, framerate.num*1000);
459 st->duration = (int64_t)nsv->duration * framerate.num;
462 if (nsv->vtag != vtag || nsv->atag != atag || nsv->vwidth != vwidth || nsv->vheight != vwidth) {
463 av_log(s, AV_LOG_TRACE, "NSV NSVs header values differ from the first one!!!\n");
468 nsv->state = NSV_HAS_READ_NSVS;
472 nsv->state = NSV_UNSYNC;
476 static int nsv_read_header(AVFormatContext *s)
478 NSVContext *nsv = s->priv_data;
481 nsv->state = NSV_UNSYNC;
482 nsv->ahead[0].data = nsv->ahead[1].data = NULL;
484 for (i = 0; i < NSV_MAX_RESYNC_TRIES; i++) {
485 if (nsv_resync(s) < 0)
487 if (nsv->state == NSV_FOUND_NSVF) {
488 err = nsv_parse_NSVf_header(s);
492 /* we need the first NSVs also... */
493 if (nsv->state == NSV_FOUND_NSVS) {
494 err = nsv_parse_NSVs_header(s);
497 break; /* we just want the first one */
500 if (s->nb_streams < 1) /* no luck so far */
502 /* now read the first chunk, so we can attempt to decode more info */
503 err = nsv_read_chunk(s, 1);
505 av_log(s, AV_LOG_TRACE, "parsed header\n");
509 static int nsv_read_chunk(AVFormatContext *s, int fill_header)
511 NSVContext *nsv = s->priv_data;
512 AVIOContext *pb = s->pb;
513 AVStream *st[2] = {NULL, NULL};
517 uint8_t auxcount; /* number of aux metadata, also 4 bits of vsize */
523 if (nsv->ahead[0].data || nsv->ahead[1].data)
524 return 0; //-1; /* hey! eat what you've in your plate first! */
530 for (i = 0; i < NSV_MAX_RESYNC_TRIES && nsv->state < NSV_FOUND_NSVS && !err; i++)
534 if (nsv->state == NSV_FOUND_NSVS)
535 err = nsv_parse_NSVs_header(s);
538 if (nsv->state != NSV_HAS_READ_NSVS && nsv->state != NSV_FOUND_BEEF)
541 auxcount = avio_r8(pb);
542 vsize = avio_rl16(pb);
543 asize = avio_rl16(pb);
544 vsize = (vsize << 4) | (auxcount >> 4);
546 av_log(s, AV_LOG_TRACE, "NSV CHUNK %d aux, %u bytes video, %d bytes audio\n", auxcount, vsize, asize);
548 for (i = 0; i < auxcount; i++) {
549 uint32_t av_unused auxtag;
550 auxsize = avio_rl16(pb);
551 auxtag = avio_rl32(pb);
552 avio_skip(pb, auxsize);
553 vsize -= auxsize + sizeof(uint16_t) + sizeof(uint32_t); /* that's becoming brain-dead */
558 if (!vsize && !asize) {
559 nsv->state = NSV_UNSYNC;
560 goto null_chunk_retry;
563 /* map back streams to v,a */
564 if (s->nb_streams > 0)
565 st[s->streams[0]->id] = s->streams[0];
566 if (s->nb_streams > 1)
567 st[s->streams[1]->id] = s->streams[1];
569 if (vsize && st[NSV_ST_VIDEO]) {
570 nst = st[NSV_ST_VIDEO]->priv_data;
571 pkt = &nsv->ahead[NSV_ST_VIDEO];
572 if ((ret = av_get_packet(pb, pkt, vsize)) < 0)
574 pkt->stream_index = st[NSV_ST_VIDEO]->index;//NSV_ST_VIDEO;
575 pkt->dts = nst->frame_offset;
576 pkt->flags |= nsv->state == NSV_HAS_READ_NSVS ? AV_PKT_FLAG_KEY : 0; /* keyframe only likely on a sync frame */
577 for (i = 0; i < FFMIN(8, vsize); i++)
578 av_log(s, AV_LOG_TRACE, "NSV video: [%d] = %02x\n", i, pkt->data[i]);
581 ((NSVStream*)st[NSV_ST_VIDEO]->priv_data)->frame_offset++;
583 if (asize && st[NSV_ST_AUDIO]) {
584 nst = st[NSV_ST_AUDIO]->priv_data;
585 pkt = &nsv->ahead[NSV_ST_AUDIO];
586 /* read raw audio specific header on the first audio chunk... */
587 /* on ALL audio chunks ?? seems so! */
588 if (asize && st[NSV_ST_AUDIO]->codecpar->codec_tag == MKTAG('P', 'C', 'M', ' ')/* && fill_header*/) {
593 channels = avio_r8(pb);
594 samplerate = avio_rl16(pb);
595 if (!channels || !samplerate)
596 return AVERROR_INVALIDDATA;
598 av_log(s, AV_LOG_TRACE, "NSV RAWAUDIO: bps %d, nchan %d, srate %d\n", bps, channels, samplerate);
600 st[NSV_ST_AUDIO]->need_parsing = AVSTREAM_PARSE_NONE; /* we know everything */
602 av_log(s, AV_LOG_TRACE, "NSV AUDIO bit/sample != 16 (%d)!!!\n", bps);
604 bps /= channels; // ???
606 st[NSV_ST_AUDIO]->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
607 samplerate /= 4;/* UGH ??? XXX */
609 st[NSV_ST_AUDIO]->codecpar->channels = channels;
610 st[NSV_ST_AUDIO]->codecpar->sample_rate = samplerate;
611 av_log(s, AV_LOG_TRACE, "NSV RAWAUDIO: bps %d, nchan %d, srate %d\n", bps, channels, samplerate);
614 if ((ret = av_get_packet(pb, pkt, asize)) < 0)
616 pkt->stream_index = st[NSV_ST_AUDIO]->index;//NSV_ST_AUDIO;
617 pkt->flags |= nsv->state == NSV_HAS_READ_NSVS ? AV_PKT_FLAG_KEY : 0; /* keyframe only likely on a sync frame */
618 if( nsv->state == NSV_HAS_READ_NSVS && st[NSV_ST_VIDEO] ) {
619 /* on a nsvs frame we have new information on a/v sync */
620 pkt->dts = (((NSVStream*)st[NSV_ST_VIDEO]->priv_data)->frame_offset-1);
621 pkt->dts *= (int64_t)1000 * nsv->framerate.den;
622 pkt->dts += (int64_t)nsv->avsync * nsv->framerate.num;
623 av_log(s, AV_LOG_TRACE, "NSV AUDIO: sync:%d, dts:%"PRId64, nsv->avsync, pkt->dts);
628 nsv->state = NSV_UNSYNC;
633 static int nsv_read_packet(AVFormatContext *s, AVPacket *pkt)
635 NSVContext *nsv = s->priv_data;
638 /* in case we don't already have something to eat ... */
639 if (!nsv->ahead[0].data && !nsv->ahead[1].data)
640 err = nsv_read_chunk(s, 0);
644 /* now pick one of the plates */
645 for (i = 0; i < 2; i++) {
646 if (nsv->ahead[i].data) {
647 /* avoid the cost of new_packet + memcpy(->data) */
648 memcpy(pkt, &nsv->ahead[i], sizeof(AVPacket));
649 nsv->ahead[i].data = NULL; /* we ate that one */
654 /* this restaurant is not provisioned :^] */
658 static int nsv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
660 NSVContext *nsv = s->priv_data;
661 AVStream *st = s->streams[stream_index];
662 NSVStream *nst = st->priv_data;
665 index = av_index_search_timestamp(st, timestamp, flags);
669 if (avio_seek(s->pb, st->index_entries[index].pos, SEEK_SET) < 0)
672 nst->frame_offset = st->index_entries[index].timestamp;
673 nsv->state = NSV_UNSYNC;
677 static int nsv_read_close(AVFormatContext *s)
679 NSVContext *nsv = s->priv_data;
681 av_freep(&nsv->nsvs_file_offset);
682 av_freep(&nsv->nsvs_timestamps);
683 if (nsv->ahead[0].data)
684 av_packet_unref(&nsv->ahead[0]);
685 if (nsv->ahead[1].data)
686 av_packet_unref(&nsv->ahead[1]);
690 static int nsv_probe(AVProbeData *p)
694 /* check file header */
695 /* streamed files might not have any header */
696 if (p->buf[0] == 'N' && p->buf[1] == 'S' &&
697 p->buf[2] == 'V' && (p->buf[3] == 'f' || p->buf[3] == 's'))
698 return AVPROBE_SCORE_MAX;
699 /* XXX: do streamed files always start at chunk boundary ?? */
700 /* or do we need to search NSVs in the byte stream ? */
701 /* seems the servers don't bother starting clean chunks... */
702 /* sometimes even the first header is at 9KB or something :^) */
703 for (i = 1; i < p->buf_size - 3; i++) {
704 if (AV_RL32(p->buf + i) == AV_RL32("NSVs")) {
705 /* Get the chunk size and check if at the end we are getting 0xBEEF */
706 int vsize = AV_RL24(p->buf+i+19) >> 4;
707 int asize = AV_RL16(p->buf+i+22);
708 int offset = i + 23 + asize + vsize + 1;
709 if (offset <= p->buf_size - 2 && AV_RL16(p->buf + offset) == 0xBEEF)
710 return 4*AVPROBE_SCORE_MAX/5;
711 score = AVPROBE_SCORE_MAX/5;
714 /* so we'll have more luck on extension... */
715 if (av_match_ext(p->filename, "nsv"))
716 return AVPROBE_SCORE_EXTENSION;
717 /* FIXME: add mime-type check */
721 AVInputFormat ff_nsv_demuxer = {
723 .long_name = NULL_IF_CONFIG_SMALL("Nullsoft Streaming Video"),
724 .priv_data_size = sizeof(NSVContext),
725 .read_probe = nsv_probe,
726 .read_header = nsv_read_header,
727 .read_packet = nsv_read_packet,
728 .read_close = nsv_read_close,
729 .read_seek = nsv_read_seek,