/*

  * NSV demuxer

  * Copyright (c) 2004 The FFmpeg Project

  *

  * first version by Francois Revol <revol@free.fr>
  *

  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either

  * version 2.1 of the License, or (at your option) any later version.

  *

  * FFmpeg is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */

 #include "libavutil/attributes.h"

 #include "libavutil/mathematics.h"

 #include "avformat.h"

 #include "internal.h"

 #include "libavutil/dict.h"

 #include "libavutil/intreadwrite.h"

 
 /* max bytes to crawl for trying to resync
  * stupid streaming servers don't start at chunk boundaries...
  */
 #define NSV_MAX_RESYNC (500*1024)
 #define NSV_MAX_RESYNC_TRIES 300
 
 /*
  * References:
  * (1) http://www.multimedia.cx/nsv-format.txt
  * seems someone came to the same conclusions as me, and updated it:
  * (2) http://www.stud.ktu.lt/~vitslav/nsv/nsv-format.txt
  *     http://www.stud.ktu.lt/~vitslav/nsv/

  * official docs
  * (3) http://ultravox.aol.com/NSVFormat.rtf

  * Sample files:
  * (S1) http://www.nullsoft.com/nsv/samples/
  * http://www.nullsoft.com/nsv/samples/faster.nsv
  * http://streamripper.sourceforge.net/openbb/read.php?TID=492&page=4
  */
 
 /*
  * notes on the header (Francois Revol):

  *
  * It is followed by strings, then a table, but nothing tells

  * where the table begins according to (1). After checking faster.nsv,
  * I believe NVSf[16-19] gives the size of the strings data
  * (that is the offset of the data table after the header).
  * After checking all samples from (S1) all confirms this.
  *

  * Then, about NSVf[12-15], faster.nsf has 179700. When viewing it in VLC,

  * I noticed there was about 1 NVSs chunk/s, so I ran
  * strings faster.nsv | grep NSVs | wc -l

  * which gave me 180. That leads me to think that NSVf[12-15] might be the

  * file length in milliseconds.
  * Let's try that:
  * 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

  * except for nsvtrailer (which doesn't have an NSVf header), it reports correct time.

  *

  * nsvtrailer.nsv (S1) does not have any NSVf header, only NSVs chunks,

  * so the header seems to not be mandatory. (for streaming).

  *

  * index slice duration check (excepts nsvtrailer.nsv):
  * 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
  */
 
 /*
  * TODO:
  * - handle timestamps !!!
  * - use index
  * - mime-type in probe()
  * - seek
  */
 
 #if 0
 struct NSVf_header {
     uint32_t chunk_tag; /* 'NSVf' */
     uint32_t chunk_size;

     uint32_t file_size; /* max 4GB ??? no one learns anything it seems :^) */

     uint32_t file_length; //unknown1;  /* what about MSB of file_size ? */
     uint32_t info_strings_size; /* size of the info strings */ //unknown2;
     uint32_t table_entries;
     uint32_t table_entries_used; /* the left ones should be -1 */
 };
 
 struct NSVs_header {
     uint32_t chunk_tag; /* 'NSVs' */
     uint32_t v4cc;      /* or 'NONE' */
     uint32_t a4cc;      /* or 'NONE' */

     uint16_t vwidth;    /* av_assert0(vwidth%16==0) */
     uint16_t vheight;   /* av_assert0(vheight%16==0) */

     uint8_t framerate;  /* value = (framerate&0x80)?frtable[frameratex0x7f]:framerate */
     uint16_t unknown;
 };
 
 struct nsv_avchunk_header {
     uint8_t vchunk_size_lsb;
     uint16_t vchunk_size_msb; /* value = (vchunk_size_msb << 4) | (vchunk_size_lsb >> 4) */
     uint16_t achunk_size;
 };
 
 struct nsv_pcm_header {
     uint8_t bits_per_sample;
     uint8_t channel_count;
     uint16_t sample_rate;
 };
 #endif
 
 /* variation from avi.h */
 /*typedef struct CodecTag {
     int id;
     unsigned int tag;
 } CodecTag;*/
 
 /* tags */
 
 #define T_NSVF MKTAG('N', 'S', 'V', 'f') /* file header */
 #define T_NSVS MKTAG('N', 'S', 'V', 's') /* chunk header */
 #define T_TOC2 MKTAG('T', 'O', 'C', '2') /* extra index marker */
 #define T_NONE MKTAG('N', 'O', 'N', 'E') /* null a/v 4CC */
 #define T_SUBT MKTAG('S', 'U', 'B', 'T') /* subtitle aux data */
 #define T_ASYN MKTAG('A', 'S', 'Y', 'N') /* async a/v aux marker */
 #define T_KEYF MKTAG('K', 'E', 'Y', 'F') /* video keyframe aux marker (addition) */
 
 #define TB_NSVF MKBETAG('N', 'S', 'V', 'f')
 #define TB_NSVS MKBETAG('N', 'S', 'V', 's')
 

 /* hardcoded stream indexes */

 #define NSV_ST_VIDEO 0
 #define NSV_ST_AUDIO 1
 #define NSV_ST_SUBT 2
 
 enum NSVStatus {
     NSV_UNSYNC,
     NSV_FOUND_NSVF,
     NSV_HAS_READ_NSVF,
     NSV_FOUND_NSVS,
     NSV_HAS_READ_NSVS,
     NSV_FOUND_BEEF,
     NSV_GOT_VIDEO,
     NSV_GOT_AUDIO,
 };
 
 typedef struct NSVStream {
     int frame_offset; /* current frame (video) or byte (audio) counter
                          (used to compute the pts) */
     int scale;

     int rate;

     int sample_size; /* audio only data */
     int start;

     int new_frame_offset; /* temporary storage (used during seek) */
     int cum_len; /* temporary storage (used during seek) */
 } NSVStream;
 

 typedef struct NSVContext {

     int  base_offset;
     int  NSVf_end;

     uint32_t *nsvs_file_offset;

     int index_entries;
     enum NSVStatus state;
     AVPacket ahead[2]; /* [v, a] if .data is !NULL there is something */
     /* cached */
     int64_t duration;
     uint32_t vtag, atag;
     uint16_t vwidth, vheight;

     int16_t avsync;

     AVRational framerate;

     uint32_t *nsvs_timestamps;

 } NSVContext;
 

 static const AVCodecTag nsv_codec_video_tags[] = {

     { AV_CODEC_ID_VP3, MKTAG('V', 'P', '3', ' ') },
     { AV_CODEC_ID_VP3, MKTAG('V', 'P', '3', '0') },
     { AV_CODEC_ID_VP3, MKTAG('V', 'P', '3', '1') },
     { AV_CODEC_ID_VP5, MKTAG('V', 'P', '5', ' ') },
     { AV_CODEC_ID_VP5, MKTAG('V', 'P', '5', '0') },
     { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', ' ') },
     { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', '0') },
     { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', '1') },
     { AV_CODEC_ID_VP6, MKTAG('V', 'P', '6', '2') },

     { AV_CODEC_ID_VP8, MKTAG('V', 'P', '8', '0') },

 /*

     { AV_CODEC_ID_VP4, MKTAG('V', 'P', '4', ' ') },
     { AV_CODEC_ID_VP4, MKTAG('V', 'P', '4', '0') },

 */

     { AV_CODEC_ID_MPEG4, MKTAG('X', 'V', 'I', 'D') }, /* cf sample xvid decoder from nsv_codec_sdk.zip */
     { AV_CODEC_ID_RAWVIDEO, MKTAG('R', 'G', 'B', '3') },
     { AV_CODEC_ID_NONE, 0 },

 };
 

 static const AVCodecTag nsv_codec_audio_tags[] = {

     { AV_CODEC_ID_MP3,       MKTAG('M', 'P', '3', ' ') },
     { AV_CODEC_ID_AAC,       MKTAG('A', 'A', 'C', ' ') },
     { AV_CODEC_ID_AAC,       MKTAG('A', 'A', 'C', 'P') },

     { AV_CODEC_ID_AAC,       MKTAG('V', 'L', 'B', ' ') },

     { AV_CODEC_ID_SPEEX,     MKTAG('S', 'P', 'X', ' ') },
     { AV_CODEC_ID_PCM_U16LE, MKTAG('P', 'C', 'M', ' ') },
     { AV_CODEC_ID_NONE,      0 },

 };
 
 //static int nsv_load_index(AVFormatContext *s);
 static int nsv_read_chunk(AVFormatContext *s, int fill_header);
 
 /* try to find something we recognize, and set the state accordingly */
 static int nsv_resync(AVFormatContext *s)
 {
     NSVContext *nsv = s->priv_data;

     AVIOContext *pb = s->pb;

     uint32_t v = 0;

     int i;

     for (i = 0; i < NSV_MAX_RESYNC; i++) {

         if (avio_feof(pb)) {

             av_log(s, AV_LOG_TRACE, "NSV EOF\n");

             nsv->state = NSV_UNSYNC;
             return -1;
         }
         v <<= 8;

         v |= avio_r8(pb);

         if (i < 8) {

             av_log(s, AV_LOG_TRACE, "NSV resync: [%d] = %02"PRIx32"\n", i, v & 0x0FF);

         }

         if ((v & 0x0000ffff) == 0xefbe) { /* BEEF */

             av_log(s, AV_LOG_TRACE, "NSV resynced on BEEF after %d bytes\n", i+1);

             nsv->state = NSV_FOUND_BEEF;
             return 0;
         }

         /* we read as big-endian, thus the MK*BE* */

         if (v == TB_NSVF) { /* NSVf */

             av_log(s, AV_LOG_TRACE, "NSV resynced on NSVf after %d bytes\n", i+1);

             nsv->state = NSV_FOUND_NSVF;
             return 0;
         }
         if (v == MKBETAG('N', 'S', 'V', 's')) { /* NSVs */

             av_log(s, AV_LOG_TRACE, "NSV resynced on NSVs after %d bytes\n", i+1);

             nsv->state = NSV_FOUND_NSVS;
             return 0;
         }

     }

     av_log(s, AV_LOG_TRACE, "NSV sync lost\n");

     return -1;
 }
 

 static int nsv_parse_NSVf_header(AVFormatContext *s)

 {
     NSVContext *nsv = s->priv_data;

     AVIOContext *pb = s->pb;

     unsigned int av_unused file_size;

     unsigned int size;

     int64_t duration;
     int strings_size;
     int table_entries;
     int table_entries_used;
 
     nsv->state = NSV_UNSYNC; /* in case we fail */

     size = avio_rl32(pb);

     if (size < 28)
         return -1;
     nsv->NSVf_end = size;
 

     file_size = (uint32_t)avio_rl32(pb);

     av_log(s, AV_LOG_TRACE, "NSV NSVf chunk_size %u\n", size);
     av_log(s, AV_LOG_TRACE, "NSV NSVf file_size %u\n", file_size);

     nsv->duration = duration = avio_rl32(pb); /* in ms */

     av_log(s, AV_LOG_TRACE, "NSV NSVf duration %"PRId64" ms\n", duration);

     // XXX: store it in AVStreams
 

     strings_size = avio_rl32(pb);
     table_entries = avio_rl32(pb);
     table_entries_used = avio_rl32(pb);

     av_log(s, AV_LOG_TRACE, "NSV NSVf info-strings size: %d, table entries: %d, bis %d\n",

             strings_size, table_entries, table_entries_used);

     if (avio_feof(pb))

         return -1;

     av_log(s, AV_LOG_TRACE, "NSV got header; filepos %"PRId64"\n", avio_tell(pb));

 
     if (strings_size > 0) {
         char *strings; /* last byte will be '\0' to play safe with str*() */
         char *p, *endp;
         char *token, *value;
         char quote;
 

         p = strings = av_mallocz((size_t)strings_size + 1);

         if (!p)
             return AVERROR(ENOMEM);

         endp = strings + strings_size;

         avio_read(pb, strings, strings_size);

         while (p < endp) {
             while (*p == ' ')
                 p++; /* strip out spaces */
             if (p >= endp-2)
                 break;
             token = p;
             p = strchr(p, '=');
             if (!p || p >= endp-2)
                 break;
             *p++ = '\0';
             quote = *p++;
             value = p;
             p = strchr(p, quote);
             if (!p || p >= endp)
                 break;
             *p++ = '\0';

             av_log(s, AV_LOG_TRACE, "NSV NSVf INFO: %s='%s'\n", token, value);

             av_dict_set(&s->metadata, token, value, 0);

         }
         av_free(strings);
     }

     if (avio_feof(pb))

         return -1;

     av_log(s, AV_LOG_TRACE, "NSV got infos; filepos %"PRId64"\n", avio_tell(pb));

 
     if (table_entries_used > 0) {

         int i;

         nsv->index_entries = table_entries_used;

         if((unsigned)table_entries_used >= UINT_MAX / sizeof(uint32_t))

             return -1;

         nsv->nsvs_file_offset = av_malloc_array((unsigned)table_entries_used, sizeof(uint32_t));

         if (!nsv->nsvs_file_offset)
             return AVERROR(ENOMEM);

         for(i=0;i<table_entries_used;i++) {
             if (avio_feof(pb))
                 return AVERROR_INVALIDDATA;

             nsv->nsvs_file_offset[i] = avio_rl32(pb) + size;

         }

 
         if(table_entries > table_entries_used &&

            avio_rl32(pb) == MKTAG('T','O','C','2')) {

             nsv->nsvs_timestamps = av_malloc_array((unsigned)table_entries_used, sizeof(uint32_t));

             if (!nsv->nsvs_timestamps)
                 return AVERROR(ENOMEM);

             for(i=0;i<table_entries_used;i++) {

                 nsv->nsvs_timestamps[i] = avio_rl32(pb);

             }
         }

     }
 

     av_log(s, AV_LOG_TRACE, "NSV got index; filepos %"PRId64"\n", avio_tell(pb));

     avio_seek(pb, nsv->base_offset + size, SEEK_SET); /* required for dumbdriving-271.nsv (2 extra bytes) */

     if (avio_feof(pb))

         return -1;
     nsv->state = NSV_HAS_READ_NSVF;
     return 0;
 }
 

 static int nsv_parse_NSVs_header(AVFormatContext *s)

 {
     NSVContext *nsv = s->priv_data;

     AVIOContext *pb = s->pb;

     uint32_t vtag, atag;
     uint16_t vwidth, vheight;

     AVRational framerate;
     int i;

     AVStream *st;
     NSVStream *nst;
 

     vtag = avio_rl32(pb);
     atag = avio_rl32(pb);
     vwidth = avio_rl16(pb);
     vheight = avio_rl16(pb);
     i = avio_r8(pb);

     av_log(s, AV_LOG_TRACE, "NSV NSVs framerate code %2x\n", i);

     if(i&0x80) { /* odd way of giving native framerates from docs */
         int t=(i & 0x7F)>>2;
         if(t<16) framerate = (AVRational){1, t+1};
         else     framerate = (AVRational){t-15, 1};
 
         if(i&1){
             framerate.num *= 1000;
             framerate.den *= 1001;
         }
 
         if((i&3)==3)      framerate.num *= 24;
         else if((i&3)==2) framerate.num *= 25;
         else              framerate.num *= 30;
     }
     else
         framerate= (AVRational){i, 1};
 

     nsv->avsync = avio_rl16(pb);

     nsv->framerate = framerate;

     av_log(s, AV_LOG_TRACE, "NSV NSVs vsize %dx%d\n", vwidth, vheight);

     /* XXX change to ap != NULL ? */
     if (s->nb_streams == 0) { /* streams not yet published, let's do that */
         nsv->vtag = vtag;
         nsv->atag = atag;
         nsv->vwidth = vwidth;
         nsv->vheight = vwidth;
         if (vtag != T_NONE) {

             int i;

             st = avformat_new_stream(s, NULL);

             if (!st)
                 goto fail;
 

             st->id = NSV_ST_VIDEO;

             nst = av_mallocz(sizeof(NSVStream));
             if (!nst)
                 goto fail;
             st->priv_data = nst;

             st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
             st->codecpar->codec_tag = vtag;
             st->codecpar->codec_id = ff_codec_get_id(nsv_codec_video_tags, vtag);
             st->codecpar->width = vwidth;
             st->codecpar->height = vheight;
             st->codecpar->bits_per_coded_sample = 24; /* depth XXX */

             avpriv_set_pts_info(st, 64, framerate.den, framerate.num);

             st->start_time = 0;

             st->duration = av_rescale(nsv->duration, framerate.num, 1000*framerate.den);

 
             for(i=0;i<nsv->index_entries;i++) {
                 if(nsv->nsvs_timestamps) {
                     av_add_index_entry(st, nsv->nsvs_file_offset[i], nsv->nsvs_timestamps[i],
                                        0, 0, AVINDEX_KEYFRAME);
                 } else {
                     int64_t ts = av_rescale(i*nsv->duration/nsv->index_entries, framerate.num, 1000*framerate.den);
                     av_add_index_entry(st, nsv->nsvs_file_offset[i], ts, 0, 0, AVINDEX_KEYFRAME);
                 }
             }

         }
         if (atag != T_NONE) {

             st = avformat_new_stream(s, NULL);

             if (!st)
                 goto fail;
 

             st->id = NSV_ST_AUDIO;

             nst = av_mallocz(sizeof(NSVStream));
             if (!nst)
                 goto fail;
             st->priv_data = nst;

             st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
             st->codecpar->codec_tag = atag;
             st->codecpar->codec_id = ff_codec_get_id(nsv_codec_audio_tags, atag);

             st->need_parsing = AVSTREAM_PARSE_FULL; /* for PCM we will read a chunk later and put correct info */

             /* set timebase to common denominator of ms and framerate */

             avpriv_set_pts_info(st, 64, 1, framerate.num*1000);

             st->start_time = 0;
             st->duration = (int64_t)nsv->duration * framerate.num;

         }
     } else {
         if (nsv->vtag != vtag || nsv->atag != atag || nsv->vwidth != vwidth || nsv->vheight != vwidth) {

             av_log(s, AV_LOG_TRACE, "NSV NSVs header values differ from the first one!!!\n");

             //return -1;
         }
     }
 
     nsv->state = NSV_HAS_READ_NSVS;
     return 0;
 fail:
     /* XXX */
     nsv->state = NSV_UNSYNC;
     return -1;
 }
 

 static int nsv_read_header(AVFormatContext *s)

 {
     NSVContext *nsv = s->priv_data;

     int i, err;

 
     nsv->state = NSV_UNSYNC;
     nsv->ahead[0].data = nsv->ahead[1].data = NULL;

     for (i = 0; i < NSV_MAX_RESYNC_TRIES; i++) {
         if (nsv_resync(s) < 0)
             return -1;

         if (nsv->state == NSV_FOUND_NSVF) {

             err = nsv_parse_NSVf_header(s);

             if (err < 0)
                 return err;
         }

             /* we need the first NSVs also... */
         if (nsv->state == NSV_FOUND_NSVS) {

             err = nsv_parse_NSVs_header(s);

             if (err < 0)
                 return err;

             break; /* we just want the first one */
         }
     }
     if (s->nb_streams < 1) /* no luck so far */
         return -1;
     /* now read the first chunk, so we can attempt to decode more info */
     err = nsv_read_chunk(s, 1);

     av_log(s, AV_LOG_TRACE, "parsed header\n");

     return err;

 }
 
 static int nsv_read_chunk(AVFormatContext *s, int fill_header)
 {
     NSVContext *nsv = s->priv_data;

     AVIOContext *pb = s->pb;

     AVStream *st[2] = {NULL, NULL};
     NSVStream *nst;
     AVPacket *pkt;
     int i, err = 0;

     uint8_t auxcount; /* number of aux metadata, also 4 bits of vsize */
     uint32_t vsize;
     uint16_t asize;
     uint16_t auxsize;

     int ret;

     if (nsv->ahead[0].data || nsv->ahead[1].data)
         return 0; //-1; /* hey! eat what you've in your plate first! */
 
 null_chunk_retry:

     if (avio_feof(pb))

         return -1;

     for (i = 0; i < NSV_MAX_RESYNC_TRIES && nsv->state < NSV_FOUND_NSVS && !err; i++)
         err = nsv_resync(s);
     if (err < 0)
         return err;
     if (nsv->state == NSV_FOUND_NSVS)

         err = nsv_parse_NSVs_header(s);

     if (err < 0)
         return err;
     if (nsv->state != NSV_HAS_READ_NSVS && nsv->state != NSV_FOUND_BEEF)
         return -1;

     auxcount = avio_r8(pb);
     vsize = avio_rl16(pb);
     asize = avio_rl16(pb);

     vsize = (vsize << 4) | (auxcount >> 4);
     auxcount &= 0x0f;

     av_log(s, AV_LOG_TRACE, "NSV CHUNK %d aux, %"PRIu32" bytes video, %d bytes audio\n", auxcount, vsize, asize);

     /* skip aux stuff */
     for (i = 0; i < auxcount; i++) {

         uint32_t av_unused auxtag;

         auxsize = avio_rl16(pb);
         auxtag = avio_rl32(pb);

         avio_skip(pb, auxsize);

         vsize -= auxsize + sizeof(uint16_t) + sizeof(uint32_t); /* that's becoming brain-dead */

     }

     if (avio_feof(pb))

         return -1;
     if (!vsize && !asize) {
         nsv->state = NSV_UNSYNC;
         goto null_chunk_retry;
     }

     /* map back streams to v,a */

     if (s->nb_streams > 0)

         st[s->streams[0]->id] = s->streams[0];

     if (s->nb_streams > 1)

         st[s->streams[1]->id] = s->streams[1];

     if (vsize && st[NSV_ST_VIDEO]) {

         nst = st[NSV_ST_VIDEO]->priv_data;
         pkt = &nsv->ahead[NSV_ST_VIDEO];

         if ((ret = av_get_packet(pb, pkt, vsize)) < 0)
             return ret;

         pkt->stream_index = st[NSV_ST_VIDEO]->index;//NSV_ST_VIDEO;

         pkt->dts = nst->frame_offset;

         pkt->flags |= nsv->state == NSV_HAS_READ_NSVS ? AV_PKT_FLAG_KEY : 0; /* keyframe only likely on a sync frame */

         for (i = 0; i < FFMIN(8, vsize); i++)

             av_log(s, AV_LOG_TRACE, "NSV video: [%d] = %02x\n", i, pkt->data[i]);

     }

     if(st[NSV_ST_VIDEO])

         ((NSVStream*)st[NSV_ST_VIDEO]->priv_data)->frame_offset++;

     if (asize && st[NSV_ST_AUDIO]) {

         nst = st[NSV_ST_AUDIO]->priv_data;
         pkt = &nsv->ahead[NSV_ST_AUDIO];
         /* read raw audio specific header on the first audio chunk... */
         /* on ALL audio chunks ?? seems so! */

         if (asize && st[NSV_ST_AUDIO]->codecpar->codec_tag == MKTAG('P', 'C', 'M', ' ')/* && fill_header*/) {

             uint8_t bps;
             uint8_t channels;
             uint16_t samplerate;

             bps = avio_r8(pb);
             channels = avio_r8(pb);
             samplerate = avio_rl16(pb);

             if (!channels || !samplerate)
                 return AVERROR_INVALIDDATA;

             asize-=4;

             av_log(s, AV_LOG_TRACE, "NSV RAWAUDIO: bps %d, nchan %d, srate %d\n", bps, channels, samplerate);

             if (fill_header) {

                 st[NSV_ST_AUDIO]->need_parsing = AVSTREAM_PARSE_NONE; /* we know everything */

                 if (bps != 16) {

                     av_log(s, AV_LOG_TRACE, "NSV AUDIO bit/sample != 16 (%d)!!!\n", bps);

                 }

                 bps /= channels; // ???

                 if (bps == 8)

                     st[NSV_ST_AUDIO]->codecpar->codec_id = AV_CODEC_ID_PCM_U8;

                 samplerate /= 4;/* UGH ??? XXX */
                 channels = 1;

                 st[NSV_ST_AUDIO]->codecpar->channels = channels;
                 st[NSV_ST_AUDIO]->codecpar->sample_rate = samplerate;

                 av_log(s, AV_LOG_TRACE, "NSV RAWAUDIO: bps %d, nchan %d, srate %d\n", bps, channels, samplerate);

             }
         }

         if ((ret = av_get_packet(pb, pkt, asize)) < 0)
             return ret;

         pkt->stream_index = st[NSV_ST_AUDIO]->index;//NSV_ST_AUDIO;

         pkt->flags |= nsv->state == NSV_HAS_READ_NSVS ? AV_PKT_FLAG_KEY : 0; /* keyframe only likely on a sync frame */

         if( nsv->state == NSV_HAS_READ_NSVS && st[NSV_ST_VIDEO] ) {
             /* on a nsvs frame we have new information on a/v sync */
             pkt->dts = (((NSVStream*)st[NSV_ST_VIDEO]->priv_data)->frame_offset-1);

             pkt->dts *= (int64_t)1000        * nsv->framerate.den;
             pkt->dts += (int64_t)nsv->avsync * nsv->framerate.num;

             av_log(s, AV_LOG_TRACE, "NSV AUDIO: sync:%d, dts:%"PRId64, nsv->avsync, pkt->dts);

         }
         nst->frame_offset++;

     }

     nsv->state = NSV_UNSYNC;
     return 0;
 }
 
 
 static int nsv_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     NSVContext *nsv = s->priv_data;
     int i, err = 0;
 
     /* in case we don't already have something to eat ... */

     if (!nsv->ahead[0].data && !nsv->ahead[1].data)

         err = nsv_read_chunk(s, 0);
     if (err < 0)
         return err;

     /* now pick one of the plates */
     for (i = 0; i < 2; i++) {
         if (nsv->ahead[i].data) {
             /* avoid the cost of new_packet + memcpy(->data) */
             memcpy(pkt, &nsv->ahead[i], sizeof(AVPacket));
             nsv->ahead[i].data = NULL; /* we ate that one */
             return pkt->size;
         }
     }

     /* this restaurant is not provisioned :^] */

     return -1;
 }
 
 static int nsv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 {

     NSVContext *nsv = s->priv_data;
     AVStream *st = s->streams[stream_index];
     NSVStream *nst = st->priv_data;
     int index;

     index = av_index_search_timestamp(st, timestamp, flags);
     if(index < 0)
         return -1;
 

     if (avio_seek(s->pb, st->index_entries[index].pos, SEEK_SET) < 0)
         return -1;
 

     nst->frame_offset = st->index_entries[index].timestamp;
     nsv->state = NSV_UNSYNC;
     return 0;

 }
 
 static int nsv_read_close(AVFormatContext *s)
 {
     NSVContext *nsv = s->priv_data;
 

     av_freep(&nsv->nsvs_file_offset);
     av_freep(&nsv->nsvs_timestamps);

     if (nsv->ahead[0].data)

         av_packet_unref(&nsv->ahead[0]);

     if (nsv->ahead[1].data)

         av_packet_unref(&nsv->ahead[1]);

     return 0;
 }
 
 static int nsv_probe(AVProbeData *p)
 {

     int i, score = 0;
 

     /* check file header */
     /* streamed files might not have any header */
     if (p->buf[0] == 'N' && p->buf[1] == 'S' &&

         p->buf[2] == 'V' && (p->buf[3] == 'f' || p->buf[3] == 's'))

         return AVPROBE_SCORE_MAX;
     /* XXX: do streamed files always start at chunk boundary ?? */
     /* or do we need to search NSVs in the byte stream ? */
     /* seems the servers don't bother starting clean chunks... */
     /* sometimes even the first header is at 9KB or something :^) */
     for (i = 1; i < p->buf_size - 3; i++) {

         if (AV_RL32(p->buf + i) == AV_RL32("NSVs")) {

             /* Get the chunk size and check if at the end we are getting 0xBEEF */

             int vsize = AV_RL24(p->buf+i+19) >> 4;
             int asize = AV_RL16(p->buf+i+22);
             int offset = i + 23 + asize + vsize + 1;
             if (offset <= p->buf_size - 2 && AV_RL16(p->buf + offset) == 0xBEEF)
                 return 4*AVPROBE_SCORE_MAX/5;
             score = AVPROBE_SCORE_MAX/5;

         }

     }
     /* so we'll have more luck on extension... */

     if (av_match_ext(p->filename, "nsv"))

         return AVPROBE_SCORE_EXTENSION;

     /* FIXME: add mime-type check */

     return score;

 }
 

 AVInputFormat ff_nsv_demuxer = {

     .name           = "nsv",
     .long_name      = NULL_IF_CONFIG_SMALL("Nullsoft Streaming Video"),
     .priv_data_size = sizeof(NSVContext),
     .read_probe     = nsv_probe,
     .read_header    = nsv_read_header,
     .read_packet    = nsv_read_packet,
     .read_close     = nsv_read_close,
     .read_seek      = nsv_read_seek,

 };