text: /*
   * NSV demuxer
   * Copyright (c) 2004 The FFmpeg Project
   *
   * 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 "avformat.h"
  #include "riff.h"
  
  //#define DEBUG
  //#define DEBUG_DUMP_INDEX // XXX dumbdriving-271.nsv breaks with it commented!!
  //#define DEBUG_SEEK
  #define CHECK_SUBSEQUENT_NSVS
  //#define DISABLE_AUDIO
  
  /* 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
  
  /*
   * First version by Francois Revol - revol@free.fr
   * 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 veiwing 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 nstrailer (which doesn't have an NSVf header), it repports 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
   */
  
  #ifdef DEBUG
  #define PRINT(_v) printf _v
  #else
  #define PRINT(_v)
  #endif
  
  #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;    /* assert(vwidth%16==0) */
      uint16_t vheight;   /* assert(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 {
      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;
      //DVDemuxContext* dv_demux;
  } NSVContext;
  
  static const AVCodecTag nsv_codec_video_tags[] = {
      { CODEC_ID_VP3, MKTAG('V', 'P', '3', ' ') },
      { CODEC_ID_VP3, MKTAG('V', 'P', '3', '0') },
      { CODEC_ID_VP3, MKTAG('V', 'P', '3', '1') },
      { CODEC_ID_VP5, MKTAG('V', 'P', '5', ' ') },
      { CODEC_ID_VP5, MKTAG('V', 'P', '5', '0') },
      { CODEC_ID_VP6, MKTAG('V', 'P', '6', ' ') },
      { CODEC_ID_VP6, MKTAG('V', 'P', '6', '0') },
      { CODEC_ID_VP6, MKTAG('V', 'P', '6', '1') },
      { CODEC_ID_VP6, MKTAG('V', 'P', '6', '2') },
  /*
      { CODEC_ID_VP4, MKTAG('V', 'P', '4', ' ') },
      { CODEC_ID_VP4, MKTAG('V', 'P', '4', '0') },
  */
      { CODEC_ID_MPEG4, MKTAG('X', 'V', 'I', 'D') }, /* cf sample xvid decoder from nsv_codec_sdk.zip */
      { CODEC_ID_RAWVIDEO, MKTAG('R', 'G', 'B', '3') },
      { CODEC_ID_NONE, 0 },
  };
  
  static const AVCodecTag nsv_codec_audio_tags[] = {
      { CODEC_ID_MP3,       MKTAG('M', 'P', '3', ' ') },
      { CODEC_ID_AAC,       MKTAG('A', 'A', 'C', ' ') },
      { CODEC_ID_AAC,       MKTAG('A', 'A', 'C', 'P') },
      { CODEC_ID_SPEEX,     MKTAG('S', 'P', 'X', ' ') },
      { CODEC_ID_PCM_U16LE, MKTAG('P', 'C', 'M', ' ') },
      { CODEC_ID_NONE,      0 },
  };
  
  //static int nsv_load_index(AVFormatContext *s);
  static int nsv_read_chunk(AVFormatContext *s, int fill_header);
  
  #ifdef DEBUG
  static void print_tag(const char *str, unsigned int tag, int size)
  {
      printf("%s: tag=%c%c%c%c\n",
             str, tag & 0xff,
             (tag >> 8) & 0xff,
             (tag >> 16) & 0xff,
             (tag >> 24) & 0xff);
  }
  #endif
  
  /* try to find something we recognize, and set the state accordingly */
  static int nsv_resync(AVFormatContext *s)
  {
      NSVContext *nsv = s->priv_data;
      ByteIOContext *pb = s->pb;
      uint32_t v = 0;
      int i;
  
      PRINT(("%s(), offset = %"PRId64", state = %d\n", __FUNCTION__, url_ftell(pb), nsv->state));
  
      //nsv->state = NSV_UNSYNC;
  
      for (i = 0; i < NSV_MAX_RESYNC; i++) {
          if (url_feof(pb)) {
              PRINT(("NSV EOF\n"));
              nsv->state = NSV_UNSYNC;
              return -1;
          }
          v <<= 8;
          v |= get_byte(pb);
  /*
          if (i < 8) {
              PRINT(("NSV resync: [%d] = %02x\n", i, v & 0x0FF));
          }
  */
  
          if ((v & 0x0000ffff) == 0xefbe) { /* BEEF */
              PRINT(("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 */
              PRINT(("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 */
              PRINT(("NSV resynced on NSVs after %d bytes\n", i+1));
              nsv->state = NSV_FOUND_NSVS;
              return 0;
          }
  
      }
      PRINT(("NSV sync lost\n"));
      return -1;
  }
  
  static int nsv_parse_NSVf_header(AVFormatContext *s, AVFormatParameters *ap)
  {
      NSVContext *nsv = s->priv_data;
      ByteIOContext *pb = s->pb;
      unsigned int file_size, size;
      int64_t duration;
      int strings_size;
      int table_entries;
      int table_entries_used;
  
      PRINT(("%s()\n", __FUNCTION__));
  
      nsv->state = NSV_UNSYNC; /* in case we fail */
  
      size = get_le32(pb);
      if (size < 28)
          return -1;
      nsv->NSVf_end = size;
  
      //s->file_size = (uint32_t)get_le32(pb);
      file_size = (uint32_t)get_le32(pb);
      PRINT(("NSV NSVf chunk_size %u\n", size));
      PRINT(("NSV NSVf file_size %u\n", file_size));
  
      nsv->duration = duration = get_le32(pb); /* in ms */
      PRINT(("NSV NSVf duration %"PRId64" ms\n", duration));
      // XXX: store it in AVStreams
  
      strings_size = get_le32(pb);
      table_entries = get_le32(pb);
      table_entries_used = get_le32(pb);
      PRINT(("NSV NSVf info-strings size: %d, table entries: %d, bis %d\n",
              strings_size, table_entries, table_entries_used));
      if (url_feof(pb))
          return -1;
  
      PRINT(("NSV got header; filepos %"PRId64"\n", url_ftell(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(strings_size + 1);
          endp = strings + strings_size;
          get_buffer(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';
              PRINT(("NSV NSVf INFO: %s='%s'\n", token, value));
              av_metadata_set(&s->metadata, token, value);
          }
          av_free(strings);
      }
      if (url_feof(pb))
          return -1;
  
      PRINT(("NSV got infos; filepos %"PRId64"\n", url_ftell(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((unsigned)table_entries_used * sizeof(uint32_t));
  
          for(i=0;i<table_entries_used;i++)
              nsv->nsvs_file_offset[i] = get_le32(pb) + size;
  
          if(table_entries > table_entries_used &&
             get_le32(pb) == MKTAG('T','O','C','2')) {
              nsv->nsvs_timestamps = av_malloc((unsigned)table_entries_used*sizeof(uint32_t));
              for(i=0;i<table_entries_used;i++) {
                  nsv->nsvs_timestamps[i] = get_le32(pb);
              }
          }
      }
  
      PRINT(("NSV got index; filepos %"PRId64"\n", url_ftell(pb)));
  
  #ifdef DEBUG_DUMP_INDEX
  #define V(v) ((v<0x20 || v > 127)?'.':v)
      /* dump index */
      PRINT(("NSV %d INDEX ENTRIES:\n", table_entries));
      PRINT(("NSV [dataoffset][fileoffset]\n", table_entries));
      for (i = 0; i < table_entries; i++) {
          unsigned char b[8];
          url_fseek(pb, size + nsv->nsvs_file_offset[i], SEEK_SET);
          get_buffer(pb, b, 8);
          PRINT(("NSV [0x%08lx][0x%08lx]: %02x %02x %02x %02x %02x %02x %02x %02x"
             "%c%c%c%c%c%c%c%c\n",
             nsv->nsvs_file_offset[i], size + nsv->nsvs_file_offset[i],
             b[0], b[1], b[2], b[3], b[4], b[5], b[6], b[7],
             V(b[0]), V(b[1]), V(b[2]), V(b[3]), V(b[4]), V(b[5]), V(b[6]), V(b[7]) ));
      }
      //url_fseek(pb, size, SEEK_SET); /* go back to end of header */
  #undef V
  #endif
  
      url_fseek(pb, nsv->base_offset + size, SEEK_SET); /* required for dumbdriving-271.nsv (2 extra bytes) */
  
      if (url_feof(pb))
          return -1;
      nsv->state = NSV_HAS_READ_NSVF;
      return 0;
  }
  
  static int nsv_parse_NSVs_header(AVFormatContext *s, AVFormatParameters *ap)
  {
      NSVContext *nsv = s->priv_data;
      ByteIOContext *pb = s->pb;
      uint32_t vtag, atag;
      uint16_t vwidth, vheight;
      AVRational framerate;
      int i;
      AVStream *st;
      NSVStream *nst;
      PRINT(("%s()\n", __FUNCTION__));
  
      vtag = get_le32(pb);
      atag = get_le32(pb);
      vwidth = get_le16(pb);
      vheight = get_le16(pb);
      i = get_byte(pb);
  
      PRINT(("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 = get_le16(pb);
      nsv->framerate = framerate;
  #ifdef DEBUG
      print_tag("NSV NSVs vtag", vtag, 0);
      print_tag("NSV NSVs atag", atag, 0);
      PRINT(("NSV NSVs vsize %dx%d\n", vwidth, vheight));
  #endif
  
      /* 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 = av_new_stream(s, NSV_ST_VIDEO);
              if (!st)
                  goto fail;
  
              nst = av_mallocz(sizeof(NSVStream));
              if (!nst)
                  goto fail;
              st->priv_data = nst;
              st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
              st->codec->codec_tag = vtag;
              st->codec->codec_id = ff_codec_get_id(nsv_codec_video_tags, vtag);
              st->codec->width = vwidth;
              st->codec->height = vheight;
              st->codec->bits_per_coded_sample = 24; /* depth XXX */
  
              av_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) {
  #ifndef DISABLE_AUDIO
              st = av_new_stream(s, NSV_ST_AUDIO);
              if (!st)
                  goto fail;
  
              nst = av_mallocz(sizeof(NSVStream));
              if (!nst)
                  goto fail;
              st->priv_data = nst;
              st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
              st->codec->codec_tag = atag;
              st->codec->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 */
              av_set_pts_info(st, 64, 1, framerate.num*1000);
              st->start_time = 0;
              st->duration = (int64_t)nsv->duration * framerate.num;
  #endif
          }
  #ifdef CHECK_SUBSEQUENT_NSVS
      } else {
          if (nsv->vtag != vtag || nsv->atag != atag || nsv->vwidth != vwidth || nsv->vheight != vwidth) {
              PRINT(("NSV NSVs header values differ from the first one!!!\n"));
              //return -1;
          }
  #endif /* CHECK_SUBSEQUENT_NSVS */
      }
  
      nsv->state = NSV_HAS_READ_NSVS;
      return 0;
  fail:
      /* XXX */
      nsv->state = NSV_UNSYNC;
      return -1;
  }
  
  static int nsv_read_header(AVFormatContext *s, AVFormatParameters *ap)
  {
      NSVContext *nsv = s->priv_data;
      int i, err;
  
      PRINT(("%s()\n", __FUNCTION__));
      PRINT(("filename '%s'\n", s->filename));
  
      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, ap);
              /* we need the first NSVs also... */
          if (nsv->state == NSV_FOUND_NSVS) {
              err = nsv_parse_NSVs_header(s, ap);
              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);
  
      PRINT(("parsed header\n"));
      return 0;
  }
  
  static int nsv_read_chunk(AVFormatContext *s, int fill_header)
  {
      NSVContext *nsv = s->priv_data;
      ByteIOContext *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;
      uint32_t auxtag;
  
      PRINT(("%s(%d)\n", __FUNCTION__, fill_header));
  
      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 (url_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, NULL);
      if (err < 0)
          return err;
      if (nsv->state != NSV_HAS_READ_NSVS && nsv->state != NSV_FOUND_BEEF)
          return -1;
  
      auxcount = get_byte(pb);
      vsize = get_le16(pb);
      asize = get_le16(pb);
      vsize = (vsize << 4) | (auxcount >> 4);
      auxcount &= 0x0f;
      PRINT(("NSV CHUNK %d aux, %u bytes video, %d bytes audio\n", auxcount, vsize, asize));
      /* skip aux stuff */
      for (i = 0; i < auxcount; i++) {
          auxsize = get_le16(pb);
          auxtag = get_le32(pb);
          PRINT(("NSV aux data: '%c%c%c%c', %d bytes\n",
                (auxtag & 0x0ff),
                ((auxtag >> 8) & 0x0ff),
                ((auxtag >> 16) & 0x0ff),
                ((auxtag >> 24) & 0x0ff),
                auxsize));
          url_fskip(pb, auxsize);
          vsize -= auxsize + sizeof(uint16_t) + sizeof(uint32_t); /* that's becoming braindead */
      }
  
      if (url_feof(pb))
          return -1;
      if (!vsize && !asize) {
          nsv->state = NSV_UNSYNC;
          goto null_chunk_retry;
      }
  
      /* map back streams to v,a */
      if (s->streams[0])
          st[s->streams[0]->id] = s->streams[0];
      if (s->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];
          av_get_packet(pb, pkt, vsize);
          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 < MIN(8, vsize); i++)
              PRINT(("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]->codec->codec_tag == MKTAG('P', 'C', 'M', ' ')/* && fill_header*/) {
              uint8_t bps;
              uint8_t channels;
              uint16_t samplerate;
              bps = get_byte(pb);
              channels = get_byte(pb);
              samplerate = get_le16(pb);
              asize-=4;
              PRINT(("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) {
                      PRINT(("NSV AUDIO bit/sample != 16 (%d)!!!\n", bps));
                  }
                  bps /= channels; // ???
                  if (bps == 8)
                      st[NSV_ST_AUDIO]->codec->codec_id = CODEC_ID_PCM_U8;
                  samplerate /= 4;/* UGH ??? XXX */
                  channels = 1;
                  st[NSV_ST_AUDIO]->codec->channels = channels;
                  st[NSV_ST_AUDIO]->codec->sample_rate = samplerate;
                  PRINT(("NSV RAWAUDIO: bps %d, nchan %d, srate %d\n", bps, channels, samplerate));
              }
          }
          av_get_packet(pb, pkt, asize);
          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;
              PRINT(("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;
  
      PRINT(("%s()\n", __FUNCTION__));
  
      /* in case we don't already have something to eat ... */
      if (nsv->ahead[0].data == NULL && nsv->ahead[1].data == NULL)
          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) {
                  PRINT(("%s: using cached packet[%d]\n", __FUNCTION__, i));
              /* 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 approvisionned :^] */
      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;
  
      url_fseek(s->pb, st->index_entries[index].pos, SEEK_SET);
      nst->frame_offset = st->index_entries[index].timestamp;
      nsv->state = NSV_UNSYNC;
      return 0;
  }
  
  static int nsv_read_close(AVFormatContext *s)
  {
  /*     int i; */
      NSVContext *nsv = s->priv_data;
  
      av_freep(&nsv->nsvs_file_offset);
      av_freep(&nsv->nsvs_timestamps);
      if (nsv->ahead[0].data)
          av_free_packet(&nsv->ahead[0]);
      if (nsv->ahead[1].data)
          av_free_packet(&nsv->ahead[1]);
  
  #if 0
  
      for(i=0;i<s->nb_streams;i++) {
          AVStream *st = s->streams[i];
          NSVStream *ast = st->priv_data;
          if(ast){
              av_free(ast->index_entries);
              av_free(ast);
          }
          av_free(st->codec->palctrl);
      }
  
  #endif
      return 0;
  }
  
  static int nsv_probe(AVProbeData *p)
  {
      int i;
  //    PRINT(("nsv_probe(), buf_size %d\n", p->buf_size));
      /* 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 (p->buf[i+0] == 'N' && p->buf[i+1] == 'S' &&
              p->buf[i+2] == 'V' && p->buf[i+3] == 's')
              return AVPROBE_SCORE_MAX-20;
      }
      /* so we'll have more luck on extension... */
      if (av_match_ext(p->filename, "nsv"))
          return AVPROBE_SCORE_MAX/2;
      /* FIXME: add mime-type check */
      return 0;
  }
  
  AVInputFormat nsv_demuxer = {
      "nsv",
      NULL_IF_CONFIG_SMALL("Nullsoft Streaming Video"),
      sizeof(NSVContext),
      nsv_probe,
      nsv_read_header,
      nsv_read_packet,
      nsv_read_close,
      nsv_read_seek,
  };
  