PeerStreamer

/*

 * "NUT" Container Format muxer and demuxer (DRAFT-200403??)

 * Copyright (c) 2003 Alex Beregszaszi

 * Copyright (c) 2004 Michael Niedermayer

 *

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

 *

 * This library 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 General Public

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

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

 *

 *

 * Visit the official site at http://www.nut.hu/

 *

 */

/*

 * TODO:

 * - index writing

 * - index packet reading support

*/

//#define DEBUG 1

#include <limits.h>

#include "avformat.h"

#include "mpegaudio.h"

#include "avi.h"

#undef NDEBUG

#include <assert.h>

//#define TRACE

//from /dev/random

#define     MAIN_STARTCODE (0x7A561F5F04ADULL + (((uint64_t)('N'<<8) + 'M')<<48))

#define   STREAM_STARTCODE (0x11405BF2F9DBULL + (((uint64_t)('N'<<8) + 'S')<<48))

#define KEYFRAME_STARTCODE (0xE4ADEECA4569ULL + (((uint64_t)('N'<<8) + 'K')<<48))

#define    INDEX_STARTCODE (0xDD672F23E64EULL + (((uint64_t)('N'<<8) + 'X')<<48))

#define     INFO_STARTCODE (0xAB68B596BA78ULL + (((uint64_t)('N'<<8) + 'I')<<48))

#define ID_STRING "nut/multimedia container\0"

#define MAX_DISTANCE (1024*16-1)

#define MAX_SHORT_DISTANCE (1024*4-1)

#define FLAG_DATA_SIZE       1

#define FLAG_KEY_FRAME       2

#define FLAG_INVALID         4

typedef struct {

    uint8_t flags;

    uint8_t stream_id_plus1;

    uint16_t size_mul;

    uint16_t size_lsb;

    int16_t timestamp_delta;

    uint8_t reserved_count;

} FrameCode;

typedef struct {

    int last_key_frame;

    int msb_timestamp_shift;

    int rate_num;

    int rate_den;

    int64_t last_pts;

    int64_t last_sync_pos;                    ///<pos of last 1/2 type frame

    int decode_delay;

} StreamContext;

typedef struct {

    AVFormatContext *avf;

    int written_packet_size;

    int64_t packet_start[3]; //0-> startcode less, 1-> short startcode 2-> long startcodes

    FrameCode frame_code[256];

    unsigned int stream_count;

    uint64_t next_startcode;     ///< stores the next startcode if it has alraedy been parsed but the stream isnt seekable

    StreamContext *stream;

    int max_distance;

    int max_short_distance;

    int rate_num;

    int rate_den;

    int short_startcode;

} NUTContext;

static char *info_table[][2]={

        {NULL                   ,  NULL }, // end

        {NULL                   ,  NULL },

        {NULL                   , "UTF8"},

        {NULL                   , "v"},

        {NULL                   , "s"},

        {"StreamId"             , "v"},

        {"SegmentId"            , "v"},

        {"StartTimestamp"       , "v"},

        {"EndTimestamp"         , "v"},

        {"Author"               , "UTF8"},

        {"Title"                , "UTF8"},

        {"Description"          , "UTF8"},

        {"Copyright"            , "UTF8"},

        {"Encoder"              , "UTF8"},

        {"Keyword"              , "UTF8"},

        {"Cover"                , "JPEG"},

        {"Cover"                , "PNG"},

};

void ff_parse_specific_params(AVCodecContext *stream, int *au_rate, int *au_ssize, int *au_scale);

static void update(NUTContext *nut, int stream_index, int64_t frame_start, int frame_type, int frame_code, int key_frame, int size, int64_t pts){

    StreamContext *stream= &nut->stream[stream_index];

    stream->last_key_frame= key_frame;

    nut->packet_start[ frame_type ]= frame_start;

    stream->last_pts= pts;

}

static void reset(AVFormatContext *s, int64_t global_ts){

    NUTContext *nut = s->priv_data;

    int i;

    for(i=0; i<s->nb_streams; i++){

        StreamContext *stream= &nut->stream[i];

        stream->last_key_frame= 1;

        stream->last_pts= av_rescale(global_ts, stream->rate_num*(int64_t)nut->rate_den, stream->rate_den*(int64_t)nut->rate_num);

    }

}

static void build_frame_code(AVFormatContext *s){

    NUTContext *nut = s->priv_data;

    int key_frame, index, pred, stream_id;

    int start=0;

    int end= 255;

    int keyframe_0_esc= s->nb_streams > 2;

    int pred_table[10];

    if(keyframe_0_esc){

        /* keyframe = 0 escape */

        FrameCode *ft= &nut->frame_code[start];

        ft->flags= FLAG_DATA_SIZE;

        ft->stream_id_plus1= 0;

        ft->size_mul=1;

        ft->timestamp_delta=0;

        start++;

    }

    for(stream_id= 0; stream_id<s->nb_streams; stream_id++){

        int start2= start + (end-start)*stream_id / s->nb_streams;

        int end2  = start + (end-start)*(stream_id+1) / s->nb_streams;

        AVCodecContext *codec = s->streams[stream_id]->codec;

        int is_audio= codec->codec_type == CODEC_TYPE_AUDIO;

        int intra_only= /*codec->intra_only || */is_audio;

        int pred_count;

        for(key_frame=0; key_frame<2; key_frame++){

            if(intra_only && keyframe_0_esc && key_frame==0)

                continue;

            {

                FrameCode *ft= &nut->frame_code[start2];

                ft->flags= FLAG_KEY_FRAME*key_frame;

                ft->flags|= FLAG_DATA_SIZE;

                ft->stream_id_plus1= stream_id + 1;

                ft->size_mul=1;

                ft->timestamp_delta=0;

                start2++;

            }

        }

        key_frame= intra_only;

#if 1

        if(is_audio){

            int frame_bytes= codec->frame_size*(int64_t)codec->bit_rate / (8*codec->sample_rate);

            int pts;

            for(pts=0; pts<2; pts++){

                for(pred=0; pred<2; pred++){

                    FrameCode *ft= &nut->frame_code[start2];

                    ft->flags= FLAG_KEY_FRAME*key_frame;

                    ft->stream_id_plus1= stream_id + 1;

                    ft->size_mul=frame_bytes + 2;

                    ft->size_lsb=frame_bytes + pred;

                    ft->timestamp_delta=pts;

                    start2++;

                }

            }

        }else{

            FrameCode *ft= &nut->frame_code[start2];

            ft->flags= FLAG_KEY_FRAME | FLAG_DATA_SIZE;

            ft->stream_id_plus1= stream_id + 1;

            ft->size_mul=1;

            ft->timestamp_delta=1;

            start2++;

        }

#endif

        if(codec->has_b_frames){

            pred_count=5;

            pred_table[0]=-2;

            pred_table[1]=-1;

            pred_table[2]=1;

            pred_table[3]=3;

            pred_table[4]=4;

        }else if(codec->codec_id == CODEC_ID_VORBIS){

            pred_count=3;

            pred_table[0]=2;

            pred_table[1]=9;

            pred_table[2]=16;

        }else{

            pred_count=1;

            pred_table[0]=1;

        }

        for(pred=0; pred<pred_count; pred++){

            int start3= start2 + (end2-start2)*pred / pred_count;

            int end3  = start2 + (end2-start2)*(pred+1) / pred_count;

            for(index=start3; index<end3; index++){

                FrameCode *ft= &nut->frame_code[index];

                ft->flags= FLAG_KEY_FRAME*key_frame;

                ft->flags|= FLAG_DATA_SIZE;

                ft->stream_id_plus1= stream_id + 1;

//FIXME use single byte size and pred from last

                ft->size_mul= end3-start3;

                ft->size_lsb= index - start3;

                ft->timestamp_delta= pred_table[pred];

            }

        }

    }

    memmove(&nut->frame_code['N'+1], &nut->frame_code['N'], sizeof(FrameCode)*(255-'N'));

    nut->frame_code['N'].flags= FLAG_INVALID;

}

static uint64_t get_v(ByteIOContext *bc)

{

    uint64_t val = 0;

    for(;;)

    {

        int tmp = get_byte(bc);

        if (tmp&0x80)

            val= (val<<7) + tmp - 0x80;

        else{

//av_log(NULL, AV_LOG_DEBUG, "get_v()= %lld\n", (val<<7) + tmp);

            return (val<<7) + tmp;

        }

    }

    return -1;

}

static int get_str(ByteIOContext *bc, char *string, unsigned int maxlen){

    unsigned int len= get_v(bc);

    if(len && maxlen)

        get_buffer(bc, string, FFMIN(len, maxlen));

    while(len > maxlen){

        get_byte(bc);

        len--;

    }

    if(maxlen)

        string[FFMIN(len, maxlen-1)]= 0;

    if(maxlen == len)

        return -1;

    else

        return 0;

}

static int64_t get_s(ByteIOContext *bc){

    int64_t v = get_v(bc) + 1;

    if (v&1) return -(v>>1);

    else     return  (v>>1);

}

static uint64_t get_vb(ByteIOContext *bc){

    uint64_t val=0;

    unsigned int i= get_v(bc);

    if(i>8)

        return UINT64_MAX;

    while(i--)

        val = (val<<8) + get_byte(bc);

//av_log(NULL, AV_LOG_DEBUG, "get_vb()= %lld\n", val);

    return val;

}

#ifdef TRACE

static inline uint64_t get_v_trace(ByteIOContext *bc, char *file, char *func, int line){

    uint64_t v= get_v(bc);

    printf("get_v %5lld / %llX in %s %s:%d\n", v, v, file, func, line);

    return v;

}

static inline int64_t get_s_trace(ByteIOContext *bc, char *file, char *func, int line){

    int64_t v= get_s(bc);

    printf("get_s %5lld / %llX in %s %s:%d\n", v, v, file, func, line);

    return v;

}

static inline uint64_t get_vb_trace(ByteIOContext *bc, char *file, char *func, int line){

    uint64_t v= get_vb(bc);

    printf("get_vb %5lld / %llX in %s %s:%d\n", v, v, file, func, line);

    return v;

}

#define get_v(bc)  get_v_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)

#define get_s(bc)  get_s_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)

#define get_vb(bc)  get_vb_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)

#endif

static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum)

{

    int64_t start, size;

    start= url_ftell(bc) - 8;

    size= get_v(bc);

    init_checksum(bc, calculate_checksum ? update_adler32 : NULL, 0);

    nut->packet_start[2] = start;

    nut->written_packet_size= size;

    return size;

}

static int check_checksum(ByteIOContext *bc){

    unsigned long checksum= get_checksum(bc);

    return checksum != get_be32(bc);

}

/**

 *

 */

static int get_length(uint64_t val){

    int i;

    for (i=7; val>>i; i+=7);

    return i;

}

static uint64_t find_any_startcode(ByteIOContext *bc, int64_t pos){

    uint64_t state=0;

    if(pos >= 0)

        url_fseek(bc, pos, SEEK_SET); //note, this may fail if the stream isnt seekable, but that shouldnt matter, as in this case we simply start where we are currently

    while(!url_feof(bc)){

        state= (state<<8) | get_byte(bc);

        if((state>>56) != 'N')

            continue;

        switch(state){

        case MAIN_STARTCODE:

        case STREAM_STARTCODE:

        case KEYFRAME_STARTCODE:

        case INFO_STARTCODE:

        case INDEX_STARTCODE:

            return state;

        }

    }

    return 0;

}

/**

 * find the given startcode.

 * @param code the startcode

 * @param pos the start position of the search, or -1 if the current position

 * @returns the position of the startcode or -1 if not found

 */

static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){

    for(;;){

        uint64_t startcode= find_any_startcode(bc, pos);

        if(startcode == code)

            return url_ftell(bc) - 8;

        else if(startcode == 0)

            return -1;

        pos=-1;

    }

}

#ifdef CONFIG_MUXERS

static void put_v(ByteIOContext *bc, uint64_t val)

{

    int i;

//av_log(NULL, AV_LOG_DEBUG, "put_v()= %lld\n", val);

    val &= 0x7FFFFFFFFFFFFFFFULL; // FIXME can only encode upto 63 bits currently

    i= get_length(val);

    for (i-=7; i>0; i-=7){

        put_byte(bc, 0x80 | (val>>i));

    }

    put_byte(bc, val&0x7f);

}

/**

 * stores a string as vb.

 */

static void put_str(ByteIOContext *bc, const char *string){

    int len= strlen(string);

    put_v(bc, len);

    put_buffer(bc, string, len);

}

static void put_s(ByteIOContext *bc, int64_t val){

    if (val<=0) put_v(bc, -2*val  );

    else        put_v(bc,  2*val-1);

}

static void put_vb(ByteIOContext *bc, uint64_t val){

    int i;

    for (i=8; val>>i; i+=8);

    put_v(bc, i>>3);

    for(i-=8; i>=0; i-=8)

        put_byte(bc, (val>>i)&0xFF);

}

#ifdef TRACE

static inline void put_v_trace(ByteIOContext *bc, uint64_t v, char *file, char *func, int line){

    printf("get_v %5lld / %llX in %s %s:%d\n", v, v, file, func, line);

    put_v(bc, v);

}

static inline void put_s_trace(ByteIOContext *bc, int64_t v, char *file, char *func, int line){

    printf("get_s %5lld / %llX in %s %s:%d\n", v, v, file, func, line);

    put_s(bc, v);

}

static inline void put_vb_trace(ByteIOContext *bc, uint64_t v, char *file, char *func, int line){

    printf("get_vb %5lld / %llX in %s %s:%d\n", v, v, file, func, line);

    put_vb(bc, v);

}

#define put_v(bc, v)  put_v_trace(bc, v, __FILE__, __PRETTY_FUNCTION__, __LINE__)

#define put_s(bc, v)  put_s_trace(bc, v, __FILE__, __PRETTY_FUNCTION__, __LINE__)

#define put_vb(bc, v)  put_vb_trace(bc, v, __FILE__, __PRETTY_FUNCTION__, __LINE__)

#endif

static int put_packetheader(NUTContext *nut, ByteIOContext *bc, int max_size, int calculate_checksum)

{

    put_flush_packet(bc);

    nut->packet_start[2]= url_ftell(bc) - 8;

    nut->written_packet_size = max_size;

    /* packet header */

    put_v(bc, nut->written_packet_size); /* forward ptr */

    if(calculate_checksum)

        init_checksum(bc, update_adler32, 0);

    return 0;

}

/**

 *

 * must not be called more then once per packet

 */

static int update_packetheader(NUTContext *nut, ByteIOContext *bc, int additional_size, int calculate_checksum){

    int64_t start= nut->packet_start[2];

    int64_t cur= url_ftell(bc);

    int size= cur - start - get_length(nut->written_packet_size)/7 - 8;

    if(calculate_checksum)

        size += 4;

    if(size != nut->written_packet_size){

        int i;

        assert( size <= nut->written_packet_size );

        url_fseek(bc, start + 8, SEEK_SET);

        for(i=get_length(size); i < get_length(nut->written_packet_size); i+=7)

            put_byte(bc, 0x80);

        put_v(bc, size);

        url_fseek(bc, cur, SEEK_SET);

        nut->written_packet_size= size; //FIXME may fail if multiple updates with differing sizes, as get_length may differ

        if(calculate_checksum)

            put_be32(bc, get_checksum(bc));

    }

    return 0;

}

static int nut_write_header(AVFormatContext *s)

{

    NUTContext *nut = s->priv_data;

    ByteIOContext *bc = &s->pb;

    AVCodecContext *codec;

    int i, j, tmp_time, tmp_flags,tmp_stream, tmp_mul, tmp_size, tmp_fields;

    nut->avf= s;

    nut->stream =

        av_mallocz(sizeof(StreamContext)*s->nb_streams);

    put_buffer(bc, ID_STRING, strlen(ID_STRING));

    put_byte(bc, 0);

    nut->packet_start[2]= url_ftell(bc);

    /* main header */

    put_be64(bc, MAIN_STARTCODE);

    put_packetheader(nut, bc, 120+5*256, 1);

    put_v(bc, 2); /* version */

    put_v(bc, s->nb_streams);

    put_v(bc, MAX_DISTANCE);

    put_v(bc, MAX_SHORT_DISTANCE);

    put_v(bc, nut->rate_num=1);

    put_v(bc, nut->rate_den=2);

    put_v(bc, nut->short_startcode=0x4EFE79);

    build_frame_code(s);

    assert(nut->frame_code['N'].flags == FLAG_INVALID);

    tmp_time= tmp_flags= tmp_stream= tmp_mul= tmp_size= /*tmp_res=*/ INT_MAX;

    for(i=0; i<256;){

        tmp_fields=0;

        tmp_size= 0;

        if(tmp_time   != nut->frame_code[i].timestamp_delta) tmp_fields=1;

        if(tmp_mul    != nut->frame_code[i].size_mul       ) tmp_fields=2;

        if(tmp_stream != nut->frame_code[i].stream_id_plus1) tmp_fields=3;

        if(tmp_size   != nut->frame_code[i].size_lsb       ) tmp_fields=4;

//        if(tmp_res    != nut->frame_code[i].res            ) tmp_fields=5;

        tmp_time  = nut->frame_code[i].timestamp_delta;

        tmp_flags = nut->frame_code[i].flags;

        tmp_stream= nut->frame_code[i].stream_id_plus1;

        tmp_mul   = nut->frame_code[i].size_mul;

        tmp_size  = nut->frame_code[i].size_lsb;

//        tmp_res   = nut->frame_code[i].res;

        for(j=0; i<256; j++,i++){

            if(nut->frame_code[i].timestamp_delta != tmp_time  ) break;

            if(nut->frame_code[i].flags           != tmp_flags ) break;

            if(nut->frame_code[i].stream_id_plus1 != tmp_stream) break;

            if(nut->frame_code[i].size_mul        != tmp_mul   ) break;

            if(nut->frame_code[i].size_lsb        != tmp_size+j) break;

//            if(nut->frame_code[i].res             != tmp_res   ) break;

        }

        if(j != tmp_mul - tmp_size) tmp_fields=6;

        put_v(bc, tmp_flags);

        put_v(bc, tmp_fields);

        if(tmp_fields>0) put_s(bc, tmp_time);

        if(tmp_fields>1) put_v(bc, tmp_mul);

        if(tmp_fields>2) put_v(bc, tmp_stream);

        if(tmp_fields>3) put_v(bc, tmp_size);

        if(tmp_fields>4) put_v(bc, 0 /*tmp_res*/);

        if(tmp_fields>5) put_v(bc, j);

    }

    update_packetheader(nut, bc, 0, 1);

    /* stream headers */

    for (i = 0; i < s->nb_streams; i++)

    {

        int nom, denom, ssize;

        codec = s->streams[i]->codec;

        put_be64(bc, STREAM_STARTCODE);

        put_packetheader(nut, bc, 120 + codec->extradata_size, 1);

        put_v(bc, i /*s->streams[i]->index*/);

        switch(codec->codec_type){

        case CODEC_TYPE_VIDEO: put_v(bc, 0); break;

        case CODEC_TYPE_AUDIO: put_v(bc, 1); break;

//        case CODEC_TYPE_TEXT : put_v(bc, 2); break;

        case CODEC_TYPE_DATA : put_v(bc, 3); break;

        default: return -1;

        }

        if (codec->codec_tag)

            put_vb(bc, codec->codec_tag);

        else if (codec->codec_type == CODEC_TYPE_VIDEO)

        {

            put_vb(bc, codec_get_bmp_tag(codec->codec_id));

        }

        else if (codec->codec_type == CODEC_TYPE_AUDIO)

        {

            put_vb(bc, codec_get_wav_tag(codec->codec_id));

        }

        else

            put_vb(bc, 0);

        ff_parse_specific_params(codec, &nom, &ssize, &denom);

        nut->stream[i].rate_num= nom;

        nut->stream[i].rate_den= denom;

        av_set_pts_info(s->streams[i], 60, denom, nom);

        put_v(bc, codec->bit_rate);

        put_vb(bc, 0); /* no language code */

        put_v(bc, nom);

        put_v(bc, denom);

        if(nom / denom < 1000)

            nut->stream[i].msb_timestamp_shift = 7;

        else

            nut->stream[i].msb_timestamp_shift = 14;

        put_v(bc, nut->stream[i].msb_timestamp_shift);

        put_v(bc, codec->has_b_frames);

        put_byte(bc, 0); /* flags: 0x1 - fixed_fps, 0x2 - index_present */

        if(codec->extradata_size){

            put_v(bc, 1);

            put_v(bc, codec->extradata_size);

            put_buffer(bc, codec->extradata, codec->extradata_size);

        }

        put_v(bc, 0); /* end of codec specific headers */

        switch(codec->codec_type)

        {

            case CODEC_TYPE_AUDIO:

                put_v(bc, codec->sample_rate);

                put_v(bc, 1);

                put_v(bc, codec->channels);

                break;

            case CODEC_TYPE_VIDEO:

                put_v(bc, codec->width);

                put_v(bc, codec->height);

                put_v(bc, codec->sample_aspect_ratio.num);

                put_v(bc, codec->sample_aspect_ratio.den);

                put_v(bc, 0); /* csp type -- unknown */

                break;

            default:

                break;

        }

        update_packetheader(nut, bc, 0, 1);

    }

    /* info header */

    put_be64(bc, INFO_STARTCODE);

    put_packetheader(nut, bc, 30+strlen(s->author)+strlen(s->title)+

        strlen(s->comment)+strlen(s->copyright)+strlen(LIBAVFORMAT_IDENT), 1);

    if (s->author[0])

    {

        put_v(bc, 9); /* type */

        put_str(bc, s->author);

    }

    if (s->title[0])

    {

        put_v(bc, 10); /* type */

        put_str(bc, s->title);

    }

    if (s->comment[0])

    {

        put_v(bc, 11); /* type */

        put_str(bc, s->comment);

    }

    if (s->copyright[0])

    {

        put_v(bc, 12); /* type */

        put_str(bc, s->copyright);

    }

    /* encoder */

    if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)){

        put_v(bc, 13); /* type */

        put_str(bc, LIBAVFORMAT_IDENT);

    }

    put_v(bc, 0); /* eof info */

    update_packetheader(nut, bc, 0, 1);

    put_flush_packet(bc);

    return 0;

}

static int64_t lsb2full(StreamContext *stream, int64_t lsb){

    int64_t mask = (1<<stream->msb_timestamp_shift)-1;

    int64_t delta= stream->last_pts - mask/2;

    return  ((lsb - delta)&mask) + delta;

}

static int nut_write_packet(AVFormatContext *s, AVPacket *pkt)

{

    NUTContext *nut = s->priv_data;

    StreamContext *stream= &nut->stream[pkt->stream_index];

    ByteIOContext *bc = &s->pb;

    int key_frame = 0, full_pts=0;

    AVCodecContext *enc;

    int64_t coded_pts;

    int frame_type, best_length, frame_code, flags, i, size_mul, size_lsb, time_delta;

    const int64_t frame_start= url_ftell(bc);

    int64_t pts= pkt->pts;

    int size= pkt->size;

    int stream_index= pkt->stream_index;

    enc = s->streams[stream_index]->codec;

    key_frame = !!(pkt->flags & PKT_FLAG_KEY);

    frame_type=0;

    if(frame_start + size + 20 - FFMAX(nut->packet_start[1], nut->packet_start[2]) > MAX_DISTANCE)

        frame_type=2;

    if(key_frame && !stream->last_key_frame)

        frame_type=2;

    if(frame_type>1){

        int64_t global_ts= av_rescale(pts, stream->rate_den*(int64_t)nut->rate_num, stream->rate_num*(int64_t)nut->rate_den);

        reset(s, global_ts);

        put_be64(bc, KEYFRAME_STARTCODE);

        put_v(bc, global_ts);

    }

    assert(stream->last_pts != AV_NOPTS_VALUE);

    coded_pts = pts & ((1<<stream->msb_timestamp_shift)-1);

    if(lsb2full(stream, coded_pts) != pts)

        full_pts=1;

    if(full_pts)

        coded_pts= pts + (1<<stream->msb_timestamp_shift);

    best_length=INT_MAX;

    frame_code= -1;

    for(i=0; i<256; i++){

        int stream_id_plus1= nut->frame_code[i].stream_id_plus1;

        int fc_key_frame;

        int length=0;

        size_mul= nut->frame_code[i].size_mul;

        size_lsb= nut->frame_code[i].size_lsb;

        time_delta= nut->frame_code[i].timestamp_delta;

        flags= nut->frame_code[i].flags;

        assert(size_mul > size_lsb);

        if(stream_id_plus1 == 0) length+= get_length(stream_index);

        else if(stream_id_plus1 - 1 != stream_index)

            continue;

        fc_key_frame= !!(flags & FLAG_KEY_FRAME);

        assert(key_frame==0 || key_frame==1);

        if(fc_key_frame != key_frame)

            continue;

        if(flags & FLAG_DATA_SIZE){

            if(size % size_mul != size_lsb)

                continue;

            length += get_length(size / size_mul);

        }else if(size != size_lsb)

            continue;

        if(full_pts && time_delta)

            continue;

        if(!time_delta){

            length += get_length(coded_pts);

        }else{

            if(time_delta != pts - stream->last_pts)

                continue;

        }

        if(length < best_length){

            best_length= length;

            frame_code=i;

        }

//    av_log(s, AV_LOG_DEBUG, "%d %d %d %d %d %d %d %d %d %d\n", key_frame, frame_type, full_pts, size, stream_index, flags, size_mul, size_lsb, stream_id_plus1, length);

    }

    assert(frame_code != -1);

    flags= nut->frame_code[frame_code].flags;

    size_mul= nut->frame_code[frame_code].size_mul;

    size_lsb= nut->frame_code[frame_code].size_lsb;

    time_delta= nut->frame_code[frame_code].timestamp_delta;

#ifdef TRACE

    best_length /= 7;

    best_length ++; //frame_code

    if(frame_type==2){

        best_length += 8; // startcode

    }

    av_log(s, AV_LOG_DEBUG, "kf:%d ft:%d pt:%d fc:%2X len:%2d size:%d stream:%d flag:%d mul:%d lsb:%d s+1:%d pts_delta:%d pts:%lld fs:%lld\n", key_frame, frame_type, full_pts ? 1 : 0, frame_code, best_length, size, stream_index, flags, size_mul, size_lsb, nut->frame_code[frame_code].stream_id_plus1,(int)(pts - stream->last_pts), pts, frame_start);

//    av_log(s, AV_LOG_DEBUG, "%d %d %d\n", stream->lru_pts_delta[0], stream->lru_pts_delta[1], stream->lru_pts_delta[2]);

#endif

    assert(frame_type != 1); //short startcode not implemented yet

    put_byte(bc, frame_code);

    if(nut->frame_code[frame_code].stream_id_plus1 == 0)

        put_v(bc, stream_index);

    if (!time_delta){

        put_v(bc, coded_pts);

    }

    if(flags & FLAG_DATA_SIZE)

        put_v(bc, size / size_mul);

    else

        assert(size == size_lsb);

    if(size > MAX_DISTANCE){

        assert(frame_type > 1);

    }

    put_buffer(bc, pkt->data, size);

    update(nut, stream_index, frame_start, frame_type, frame_code, key_frame, size, pts);

    return 0;

}

static int nut_write_trailer(AVFormatContext *s)

{

    NUTContext *nut = s->priv_data;

    ByteIOContext *bc = &s->pb;

#if 0

    int i;

    /* WRITE INDEX */

    for (i = 0; s->nb_streams; i++)

    {

        put_be64(bc, INDEX_STARTCODE);

        put_packetheader(nut, bc, 64, 1);

        put_v(bc, s->streams[i]->id);

        put_v(bc, ...);

        update_packetheader(nut, bc, 0, 1);

    }

#endif

    put_flush_packet(bc);

    av_freep(&nut->stream);

    return 0;

}

#endif //CONFIG_MUXERS

static int nut_probe(AVProbeData *p)

{

    int i;

    uint64_t code= 0xff;

    for (i = 0; i < p->buf_size; i++) {

        code = (code << 8) | p->buf[i];

        if (code == MAIN_STARTCODE)

            return AVPROBE_SCORE_MAX;

    }

    return 0;

}

static int decode_main_header(NUTContext *nut){

    AVFormatContext *s= nut->avf;

    ByteIOContext *bc = &s->pb;

    uint64_t tmp;

    int i, j, tmp_stream, tmp_mul, tmp_time, tmp_size, count, tmp_res;

    get_packetheader(nut, bc, 1);

    tmp = get_v(bc);

    if (tmp != 2){

        av_log(s, AV_LOG_ERROR, "bad version (%"PRId64")\n", tmp);

        return -1;

    }

    nut->stream_count = get_v(bc);

    if(nut->stream_count > MAX_STREAMS){

        av_log(s, AV_LOG_ERROR, "too many streams\n");

        return -1;

    }

    nut->max_distance = get_v(bc);

    nut->max_short_distance = get_v(bc);

    nut->rate_num= get_v(bc);

    nut->rate_den= get_v(bc);

    nut->short_startcode= get_v(bc);

    if(nut->short_startcode>>16 != 'N'){

        av_log(s, AV_LOG_ERROR, "invalid short startcode %X\n", nut->short_startcode);

        return -1;

    }

    for(i=0; i<256;){

        int tmp_flags = get_v(bc);

        int tmp_fields= get_v(bc);

        if(tmp_fields>0) tmp_time  = get_s(bc);

        if(tmp_fields>1) tmp_mul   = get_v(bc);

        if(tmp_fields>2) tmp_stream= get_v(bc);

        if(tmp_fields>3) tmp_size  = get_v(bc);

        else             tmp_size  = 0;

        if(tmp_fields>4) tmp_res   = get_v(bc);

        else             tmp_res   = 0;

        if(tmp_fields>5) count     = get_v(bc);

        else             count     = tmp_mul - tmp_size;

        while(tmp_fields-- > 6)

           get_v(bc);

        if(count == 0 || i+count > 256){

            av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);

            return -1;

        }

        if(tmp_stream > nut->stream_count + 1){

            av_log(s, AV_LOG_ERROR, "illegal stream number\n");

            return -1;

        }

        for(j=0; j<count; j++,i++){

            nut->frame_code[i].flags           = tmp_flags ;

            nut->frame_code[i].timestamp_delta = tmp_time  ;

            nut->frame_code[i].stream_id_plus1 = tmp_stream;

            nut->frame_code[i].size_mul        = tmp_mul   ;

            nut->frame_code[i].size_lsb        = tmp_size+j;

            nut->frame_code[i].reserved_count  = tmp_res   ;

        }

    }

    if(nut->frame_code['N'].flags != FLAG_INVALID){

        av_log(s, AV_LOG_ERROR, "illegal frame_code table\n");

        return -1;

    }

    if(check_checksum(bc)){

        av_log(s, AV_LOG_ERROR, "Main header checksum mismatch\n");

        return -1;

    }

    return 0;

}

static int decode_stream_header(NUTContext *nut){

    AVFormatContext *s= nut->avf;

    ByteIOContext *bc = &s->pb;

    int class, nom, denom, stream_id;

    uint64_t tmp;

    AVStream *st;

    get_packetheader(nut, bc, 1);

    stream_id= get_v(bc);

    if(stream_id >= nut->stream_count || s->streams[stream_id])

        return -1;

    st = av_new_stream(s, stream_id);

    if (!st)

        return AVERROR_NOMEM;

    class = get_v(bc);

    tmp = get_vb(bc);

    st->codec->codec_tag= tmp;

    switch(class)

    {

        case 0:

            st->codec->codec_type = CODEC_TYPE_VIDEO;

            st->codec->codec_id = codec_get_bmp_id(tmp);

            if (st->codec->codec_id == CODEC_ID_NONE)

                av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");

            break;

        case 1:

        case 32: //compatibility

            st->codec->codec_type = CODEC_TYPE_AUDIO;

            st->codec->codec_id = codec_get_wav_id(tmp);

            if (st->codec->codec_id == CODEC_ID_NONE)

                av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");

            break;

        case 2:

//            st->codec->codec_type = CODEC_TYPE_TEXT;

//            break;

        case 3:

            st->codec->codec_type = CODEC_TYPE_DATA;

            break;

        default:

            av_log(s, AV_LOG_ERROR, "Unknown stream class (%d)\n", class);

            return -1;

    }

    s->bit_rate += get_v(bc);

    get_vb(bc); /* language code */

    nom = get_v(bc);

    denom = get_v(bc);

    nut->stream[stream_id].msb_timestamp_shift = get_v(bc);

    st->codec->has_b_frames=

    nut->stream[stream_id].decode_delay= get_v(bc);

    get_byte(bc); /* flags */

    /* codec specific data headers */

    while(get_v(bc) != 0){

        st->codec->extradata_size= get_v(bc);

        if((unsigned)st->codec->extradata_size > (1<<30))

            return -1;

        st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);

        get_buffer(bc, st->codec->extradata, st->codec->extradata_size);

//            url_fskip(bc, get_v(bc));

    }

    if (st->codec->codec_type == CODEC_TYPE_VIDEO) /* VIDEO */

    {

        st->codec->width = get_v(bc);

        st->codec->height = get_v(bc);

        st->codec->sample_aspect_ratio.num= get_v(bc);

        st->codec->sample_aspect_ratio.den= get_v(bc);

        get_v(bc); /* csp type */

    }

    if (st->codec->codec_type == CODEC_TYPE_AUDIO) /* AUDIO */

    {

        st->codec->sample_rate = get_v(bc);

        get_v(bc); // samplerate_den

        st->codec->channels = get_v(bc);

    }

    if(check_checksum(bc)){

        av_log(s, AV_LOG_ERROR, "Stream header %d checksum mismatch\n", stream_id);

        return -1;

    }

    av_set_pts_info(s->streams[stream_id], 60, denom, nom);

    nut->stream[stream_id].rate_num= nom;

    nut->stream[stream_id].rate_den= denom;

    return 0;

}

static int decode_info_header(NUTContext *nut){

    AVFormatContext *s= nut->avf;

    ByteIOContext *bc = &s->pb;

    get_packetheader(nut, bc, 1);

    for(;;){

        int id= get_v(bc);

        char *name, *type, custom_name[256], custom_type[256];

        if(!id)

            break;

        else if(id >= sizeof(info_table)/sizeof(info_table[0])){

            av_log(s, AV_LOG_ERROR, "info id is too large %d %zd\n", id, sizeof(info_table)/sizeof(info_table[0]));

            return -1;

        }

        type= info_table[id][1];

        name= info_table[id][0];

//av_log(s, AV_LOG_DEBUG, "%d %s %s\n", id, type, name);

        if(!type){

            get_str(bc, custom_type, sizeof(custom_type));

            type= custom_type;

        }

        if(!name){

            get_str(bc, custom_name, sizeof(custom_name));

            name= custom_name;

        }

        if(!strcmp(type, "v")){

            get_v(bc);

        }else{

            if(!strcmp(name, "Author"))

                get_str(bc, s->author, sizeof(s->author));

            else if(!strcmp(name, "Title"))

                get_str(bc, s->title, sizeof(s->title));

            else if(!strcmp(name, "Copyright"))

                get_str(bc, s->copyright, sizeof(s->copyright));

            else if(!strcmp(name, "Description"))

                get_str(bc, s->comment, sizeof(s->comment));

            else

                get_str(bc, NULL, 0);

        }

    }

    if(check_checksum(bc)){

        av_log(s, AV_LOG_ERROR, "Info header checksum mismatch\n");

        return -1;

    }

    return 0;

}

static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)

{

    NUTContext *nut = s->priv_data;

    ByteIOContext *bc = &s->pb;

    int64_t pos;

    int inited_stream_count;

    nut->avf= s;

    /* main header */

    pos=0;

    for(;;){

        pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;

        if (pos<0){

            av_log(s, AV_LOG_ERROR, "no main startcode found\n");

            return -1;

        }

        if(decode_main_header(nut) >= 0)

            break;

    }

    s->bit_rate = 0;

    nut->stream = av_malloc(sizeof(StreamContext)*nut->stream_count);

    /* stream headers */

    pos=0;

    for(inited_stream_count=0; inited_stream_count < nut->stream_count;){

        pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;

        if (pos<0+1){

            av_log(s, AV_LOG_ERROR, "not all stream headers found\n");

            return -1;

        }

        if(decode_stream_header(nut) >= 0)

            inited_stream_count++;

    }

    /* info headers */

    pos=0;

    for(;;){

        uint64_t startcode= find_any_startcode(bc, pos);

        pos= url_ftell(bc);

        if(startcode==0){

            av_log(s, AV_LOG_ERROR, "EOF before video frames\n");

            return -1;

        }else if(startcode == KEYFRAME_STARTCODE){

            nut->next_startcode= startcode;

            break;

        }else if(startcode != INFO_STARTCODE){

            continue;

        }

        decode_info_header(nut);

    }

    return 0;

}

static int decode_frame_header(NUTContext *nut, int *key_frame_ret, int64_t *pts_ret, int *stream_id_ret, int frame_code, int frame_type, int64_t frame_start){

    AVFormatContext *s= nut->avf;

    StreamContext *stream;

    ByteIOContext *bc = &s->pb;

    int size, flags, size_mul, size_lsb, stream_id, time_delta;

    int64_t pts = 0;

    if(frame_type < 2 && frame_start - nut->packet_start[2] > nut->max_distance){

        av_log(s, AV_LOG_ERROR, "last frame must have been damaged\n");

        return -1;

    }

    if(frame_type)

        nut->packet_start[ frame_type ]= frame_start; //otherwise 1 goto 1 may happen

    flags= nut->frame_code[frame_code].flags;

    size_mul= nut->frame_code[frame_code].size_mul;

    size_lsb= nut->frame_code[frame_code].size_lsb;

    stream_id= nut->frame_code[frame_code].stream_id_plus1 - 1;

    time_delta= nut->frame_code[frame_code].timestamp_delta;

    if(stream_id==-1)

        stream_id= get_v(bc);

    if(stream_id >= s->nb_streams){

        av_log(s, AV_LOG_ERROR, "illegal stream_id\n");

        return -1;

    }

    stream= &nut->stream[stream_id];

//    av_log(s, AV_LOG_DEBUG, "ft:%d ppts:%d %d %d\n", frame_type, stream->lru_pts_delta[0], stream->lru_pts_delta[1], stream->lru_pts_delta[2]);

    *key_frame_ret= !!(flags & FLAG_KEY_FRAME);

    if(!time_delta){

        int64_t mask = (1<<stream->msb_timestamp_shift)-1;

        pts= get_v(bc);

        if(pts > mask){

            pts -= mask+1;

        }else{

            if(stream->last_pts == AV_NOPTS_VALUE){

                av_log(s, AV_LOG_ERROR, "no reference pts available\n");

                return -1;

            }

            pts= lsb2full(stream, pts);

        }

    }else{

        if(stream->last_pts == AV_NOPTS_VALUE){

            av_log(s, AV_LOG_ERROR, "no reference pts available\n");

            return -1;

        }

        pts= stream->last_pts + time_delta;

    }

    if(*key_frame_ret){

//        av_log(s, AV_LOG_DEBUG, "stream:%d start:%lld pts:%lld length:%lld\n",stream_id, frame_start, av_pts, frame_start - nut->stream[stream_id].last_sync_pos);

        av_add_index_entry(

            s->streams[stream_id],

            frame_start,

            pts,

            frame_start - nut->stream[stream_id].last_sync_pos,

            AVINDEX_KEYFRAME);

        nut->stream[stream_id].last_sync_pos= frame_start;

//                assert(nut->packet_start == frame_start);

    }

    assert(size_mul > size_lsb);

    size= size_lsb;

    if(flags & FLAG_DATA_SIZE)

        size+= size_mul*get_v(bc);

#ifdef TRACE

av_log(s, AV_LOG_DEBUG, "fs:%lld fc:%d ft:%d kf:%d pts:%lld size:%d mul:%d lsb:%d flags:%d delta:%d\n", frame_start, frame_code, frame_type, *key_frame_ret, pts, size, size_mul, size_lsb, flags, time_delta);

#endif

    if(frame_type==0 && url_ftell(bc) - nut->packet_start[2] + size > nut->max_distance){

        av_log(s, AV_LOG_ERROR, "frame size too large\n");

        return -1;

    }

    *stream_id_ret = stream_id;

    *pts_ret = pts;

    update(nut, stream_id, frame_start, frame_type, frame_code, *key_frame_ret, size, pts);

    return size;

}

static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code, int frame_type, int64_t frame_start){

    AVFormatContext *s= nut->avf;

    ByteIOContext *bc = &s->pb;

    int size, stream_id, key_frame, discard;

    int64_t pts, last_IP_pts;

    size= decode_frame_header(nut, &key_frame, &pts, &stream_id, frame_code, frame_type, frame_start);

    if(size < 0)

        return -1;

    discard= s->streams[ stream_id ]->discard;

    last_IP_pts= s->streams[ stream_id ]->last_IP_pts;

    if(  (discard >= AVDISCARD_NONKEY && !key_frame)

       ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)

       || discard >= AVDISCARD_ALL){

        url_fskip(bc, size);

        return 1;

    }

    av_get_packet(bc, pkt, size);

    pkt->stream_index = stream_id;

    if (key_frame)

        pkt->flags |= PKT_FLAG_KEY;

    pkt->pts = pts;

    return 0;

}

static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    NUTContext *nut = s->priv_data;

    ByteIOContext *bc = &s->pb;

    int i, frame_code=0, ret;

    for(;;){

        int64_t pos= url_ftell(bc);

        int frame_type= 0;

        uint64_t tmp= nut->next_startcode;

        nut->next_startcode=0;

        if (url_feof(bc))

            return -1;

        if(tmp){

            pos-=8;

        }else{

            frame_code = get_byte(bc);

            if(frame_code == 'N'){

                tmp= frame_code;

                for(i=1; i<8; i++)

                    tmp = (tmp<<8) + get_byte(bc);

            }

        }

        switch(tmp){

        case MAIN_STARTCODE:

        case STREAM_STARTCODE:

        case INDEX_STARTCODE:

            get_packetheader(nut, bc, 0);

            assert(nut->packet_start[2] == pos);

            url_fseek(bc, nut->written_packet_size, SEEK_CUR);

            break;

        case INFO_STARTCODE:

            if(decode_info_header(nut)<0)

                goto resync;

            break;

        case KEYFRAME_STARTCODE:

            frame_type = 2;

            reset(s, get_v(bc));

            frame_code = get_byte(bc);

        case 0:

            ret= decode_frame(nut, pkt, frame_code, frame_type, pos);

            if(ret==0)

                return 0;

            else if(ret==1) //ok but discard packet

                break;

        default:

resync:

av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", nut->packet_start[2]+1);

            tmp= find_any_startcode(bc, nut->packet_start[2]+1);

            if(tmp==0)

                return -1;

av_log(s, AV_LOG_DEBUG, "sync\n");

            nut->next_startcode= tmp;

        }

    }

}

static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){

    NUTContext *nut = s->priv_data;

    StreamContext *stream;

    ByteIOContext *bc = &s->pb;

    int64_t pos, pts;