PeerStreamer

/*

 * 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

 */

#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);

#define print_tag(str, tag, size)       \

    av_dlog(NULL, "%s: tag=%c%c%c%c\n", \

            str, tag & 0xff,            \

            (tag >> 8) & 0xff,          \

            (tag >> 16) & 0xff,         \

            (tag >> 24) & 0xff);

/* 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;

    av_dlog(s, "%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)) {

            av_dlog(s, "NSV EOF\n");

            nsv->state = NSV_UNSYNC;

            return -1;

        }

        v <<= 8;

        v |= get_byte(pb);

        if (i < 8) {

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

        }

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

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

            nsv->state = NSV_FOUND_NSVS;

            return 0;

        }

    }

    av_dlog(s, "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;

    av_dlog(s, "%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);

    av_dlog(s, "NSV NSVf chunk_size %u\n", size);

    av_dlog(s, "NSV NSVf file_size %u\n", file_size);

    nsv->duration = duration = get_le32(pb); /* in ms */

    av_dlog(s, "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);

    av_dlog(s, "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;

    av_dlog(s, "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';

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

            av_metadata_set2(&s->metadata, token, value, 0);

        }

        av_free(strings);

    }

    if (url_feof(pb))

        return -1;

    av_dlog(s, "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);

            }

        }

    }

    av_dlog(s, "NSV got index; filepos %"PRId64"\n", url_ftell(pb));

#ifdef DEBUG_DUMP_INDEX

#define V(v) ((v<0x20 || v > 127)?'.':v)

    /* dump index */

    av_dlog(s, "NSV %d INDEX ENTRIES:\n", table_entries);

    av_dlog(s, "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);

        av_dlog(s, "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;

    av_dlog(s, "%s()\n", __FUNCTION__);

    vtag = get_le32(pb);

    atag = get_le32(pb);

    vwidth = get_le16(pb);

    vheight = get_le16(pb);

    i = get_byte(pb);

    av_dlog(s, "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;

    print_tag("NSV NSVs vtag", vtag, 0);

    print_tag("NSV NSVs atag", atag, 0);

    av_dlog(s, "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 = 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) {

            av_dlog(s, "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;

    av_dlog(s, "%s()\n", __FUNCTION__);

    av_dlog(s, "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);

    av_dlog(s, "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;

    av_dlog(s, "%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;

    av_dlog(s, "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);

        av_dlog(s, "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 < FFMIN(8, vsize); i++)

            av_dlog(s, "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;

            av_dlog(s, "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_dlog(s, "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;

                av_dlog(s, "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;

            av_dlog(s, "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;

    av_dlog(s, "%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) {

            av_dlog(s, "%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;

    av_dlog(NULL, "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 ff_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,

};