updating nut demuxer to latest spec

no muxing yet
no index yet
no seeking yet
libnuts crcs dont match mine (didnt investigate yet)
samplerate is stored wrong by libnut (demuxer has a workaround)
code is not clean or beautifull yet, but i thought its better to commit early before someone unneccesarily wastes his time duplicating the work
demuxer split from muxer

Originally committed as revision 6966 to svn://svn.ffmpeg.org/ffmpeg/trunk

4 files changed, 788 insertions, 3 deletions

diff --git a/libavformat/Makefile b/libavformat/Makefile
index 2f3ef01081..0bff900e11 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -73,8 +73,8 @@ OBJS-$(CONFIG_MPEGTS_MUXER)              += mpegtsenc.o
 OBJS-$(CONFIG_MPJPEG_MUXER)              += mpjpeg.o
 OBJS-$(CONFIG_MXF_DEMUXER)               += mxf.o
 OBJS-$(CONFIG_NSV_DEMUXER)               += nsvdec.o riff.o
-OBJS-$(CONFIG_NUT_DEMUXER)               += nut.o riff.o
-OBJS-$(CONFIG_NUT_MUXER)                 += nut.o riff.o
+OBJS-$(CONFIG_NUT_DEMUXER)               += nutdec.o riff.o
+#OBJS-$(CONFIG_NUT_MUXER)                 += nutenc.o riff.o
 OBJS-$(CONFIG_NUV_DEMUXER)               += nuv.o riff.o
 OBJS-$(CONFIG_OGG_DEMUXER)               += ogg2.o           \
                                             oggparsevorbis.o \
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 5536ea9e6b..aad7435ae8 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -249,7 +249,7 @@ void av_register_all(void)
     av_register_input_format(&nut_demuxer);
 #endif
 #ifdef CONFIG_NUT_MUXER
-    av_register_output_format(&nut_muxer);
+//    av_register_output_format(&nut_muxer);
 #endif
 #ifdef CONFIG_NUV_DEMUXER
     av_register_input_format(&nuv_demuxer);
diff --git a/libavformat/nut.h b/libavformat/nut.h
new file mode 100644
index 0000000000..af42a57720
--- /dev/null
+++ b/libavformat/nut.h
@@ -0,0 +1,94 @@
+/*
+ * "NUT" Container Format (de)muxer
+ * Copyright (c) 2006 Michael Niedermayer
+ *
+ * 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 <limits.h>
+#include "avformat.h"
+#include "crc.h"
+//#include "mpegaudio.h"
+#include "riff.h"
+//#include "adler32.h"
+
+#define      MAIN_STARTCODE (0x7A561F5F04ADULL + (((uint64_t)('N'<<8) + 'M')<<48))
+#define    STREAM_STARTCODE (0x11405BF2F9DBULL + (((uint64_t)('N'<<8) + 'S')<<48))
+#define SYNCPOINT_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*32-1)
+
+typedef enum{
+    FLAG_KEY        =   1, ///<if set, frame is keyframe
+    FLAG_EOR        =   2, ///<if set, stream has no relevance on presentation. (EOR)
+    FLAG_CODED_PTS  =   8, ///<if set, coded_pts is in the frame header
+    FLAG_STREAM_ID  =  16, ///<if set, stream_id is coded in the frame header
+    FLAG_SIZE_MSB   =  32, ///<if set, data_size_msb is at frame header, otherwise data_size_msb is 0
+    FLAG_CHECKSUM   =  64, ///<if set then the frame header contains a checksum
+    FLAG_RESERVED   = 128, ///<if set, reserved_count is coded in the frame header
+    FLAG_CODED      =4096, ///<if set, coded_flags are stored in the frame header.
+    FLAG_INVALID    =8192, ///<if set, frame_code is invalid.
+}flag_t;
+
+typedef struct {
+    uint32_t pos; //64gb limit if div16 (change this to 64 if thats too little)
+    uint64_t global_key_pts;
+    uint32_t back_ptr_div16; //is stored /16
+} syncpoint_t;
+
+typedef struct {
+    uint16_t flags;
+    uint8_t  stream_id;
+    uint16_t size_mul;
+    uint16_t size_lsb;
+    int16_t  pts_delta;
+    uint8_t  reserved_count;
+} FrameCode; // maybe s/FrameCode/framecode_t/ or change all to java style but dont mix
+
+typedef struct {
+    int last_key_frame;  ///<was the last frame a keyfraeme
+    int64_t last_pts;
+    int time_base_id;
+    AVRational time_base;
+    int msb_pts_shift;
+    int max_pts_distance;
+    int decode_delay; //FIXME duplicate of has_b_frames
+} StreamContext;// maybe s/StreamContext/streamcontext_t/
+
+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];
+    uint64_t next_startcode;     ///< stores the next startcode if it has alraedy been parsed but the stream isnt seekable
+    StreamContext *stream;
+    unsigned int max_distance;
+    unsigned int time_base_count;
+    int64_t last_syncpoint_pos;
+    AVRational *time_base;
+} NUTContext;
+
+
+//FIXME move to a common spot, like crc.c/h
+static unsigned long av_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf, unsigned int len){
+    return av_crc(av_crc04C11DB7, checksum, buf, len);
+}
diff --git a/libavformat/nutdec.c b/libavformat/nutdec.c
new file mode 100644
index 0000000000..5a3caabe89
--- /dev/null
+++ b/libavformat/nutdec.c
@@ -0,0 +1,691 @@
+/*
+ * "NUT" Container Format demuxer
+ * Copyright (c) 2004-2006 Michael Niedermayer
+ * Copyright (c) 2003 Alex Beregszaszi
+ *
+ * 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 "nut.h"
+
+#undef NDEBUG
+#include <assert.h>
+
+static uint64_t get_v(ByteIOContext *bc/*, maxstuffing*/){
+    uint64_t val = 0;
+
+    for(;;)
+    {
+        int tmp = get_byte(bc);
+
+//         if(tmp=0x80){
+//             if(!maxstuffing-- || val)
+//                 return -1;
+//         }
+
+        if (tmp&0x80)
+            val= (val<<7) + tmp - 0x80;
+        else{
+            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_fourcc(ByteIOContext *bc){
+    unsigned int len= get_v(bc);
+
+    if     (len==2) return get_le16(bc);
+    else if(len==4) return get_le32(bc);
+    else            return -1;
+}
+
+#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 %5"PRId64" / %"PRIX64" 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 %5"PRId64" / %"PRIX64" 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 %5"PRId64" / %"PRIX64" 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 ? av_crc04C11DB7_update : NULL, 1);
+
+//    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);
+
+    av_log(NULL, AV_LOG_ERROR, "%08X %08X\n", checksum, (int)get_be32(bc));
+
+    return 0;
+}
+
+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 SYNCPOINT_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;
+    }
+}
+
+static int64_t lsb2full(StreamContext *stream, int64_t lsb){
+    int64_t mask = (1<<stream->msb_pts_shift)-1;
+    int64_t delta= stream->last_pts - mask/2;
+    return  ((lsb - delta)&mask) + delta;
+}
+
+static int nut_probe(AVProbeData *p){
+    int i;
+    uint64_t code= 0;
+
+    for (i = 0; i < p->buf_size; i++) {
+        code = (code << 8) | p->buf[i];
+        if (code == MAIN_STARTCODE)
+            return AVPROBE_SCORE_MAX;
+    }
+    return 0;
+}
+
+#define GET_V(dst, check) \
+    tmp= get_v(bc);\
+    if(!(check)){\
+        av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);\
+        return -1;\
+    }\
+    dst= tmp;
+
+static int skip_reserved(ByteIOContext *bc, int64_t pos){
+    pos -= url_ftell(bc);
+
+    if(pos<0){
+        url_fseek(bc, pos, SEEK_CUR);
+        return -1;
+    }else{
+        while(pos--)
+            get_byte(bc);
+        return 0;
+    }
+}
+
+static int decode_main_header(NUTContext *nut){
+    AVFormatContext *s= nut->avf;
+    ByteIOContext *bc = &s->pb;
+    uint64_t tmp, end;
+    unsigned int stream_count;
+    int i, j, tmp_stream, tmp_mul, tmp_pts, tmp_size, count, tmp_res;
+
+    end= get_packetheader(nut, bc, 1);
+    end += url_ftell(bc) - 4;
+
+    GET_V(tmp              , tmp >=2 && tmp <= 3)
+    GET_V(stream_count     , tmp > 0 && tmp <=MAX_STREAMS)
+
+    nut->max_distance = get_v(bc);
+    if(nut->max_distance > 65536){
+        av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
+        nut->max_distance= 65536;
+    }
+
+    GET_V(nut->time_base_count, tmp>0 && tmp<INT_MAX / sizeof(AVRational))
+    nut->time_base= av_malloc(nut->time_base_count * sizeof(AVRational));
+
+    for(i=0; i<nut->time_base_count; i++){
+        GET_V(nut->time_base[i].num, tmp>0 && tmp<(1ULL<<31))
+        GET_V(nut->time_base[i].den, tmp>0 && tmp<(1ULL<<31))
+        if(ff_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1){
+            av_log(s, AV_LOG_ERROR, "time base invalid\n");
+            return -1;
+        }
+    }
+    tmp_pts=0;
+    tmp_mul=1;
+    tmp_stream=0;
+    for(i=0; i<256;){
+        int tmp_flags = get_v(bc);
+        int tmp_fields= get_v(bc);
+        if(tmp_fields>0) tmp_pts   = 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 >= stream_count){
+            av_log(s, AV_LOG_ERROR, "illegal stream number\n");
+            return -1;
+        }
+
+        for(j=0; j<count; j++,i++){
+            if (i == 'N') {
+                nut->frame_code[i].flags= FLAG_INVALID;
+                j--;
+                continue;
+            }
+            nut->frame_code[i].flags           = tmp_flags ;
+            nut->frame_code[i].pts_delta       = tmp_pts   ;
+            nut->frame_code[i].stream_id       = 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   ;
+        }
+    }
+    assert(nut->frame_code['N'].flags == FLAG_INVALID);
+
+    if(skip_reserved(bc, end) || check_checksum(bc)){
+        av_log(s, AV_LOG_ERROR, "Main header checksum mismatch\n");
+        return -1;
+    }
+
+    nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
+    for(i=0; i<stream_count; i++){
+        av_new_stream(s, i);
+    }
+
+    return 0;
+}
+
+static int decode_stream_header(NUTContext *nut){
+    AVFormatContext *s= nut->avf;
+    ByteIOContext *bc = &s->pb;
+    StreamContext *stc;
+    int class, nom, denom, stream_id;
+    uint64_t tmp, end;
+    AVStream *st;
+
+    end= get_packetheader(nut, bc, 1);
+    end += url_ftell(bc) - 4;
+
+    GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base.num);
+    stc= &nut->stream[stream_id];
+
+    st = s->streams[stream_id];
+    if (!st)
+        return AVERROR_NOMEM;
+
+    class = get_v(bc);
+    tmp = get_fourcc(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:
+            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;
+    }
+    GET_V(stc->time_base_id    , tmp < nut->time_base_count);
+    GET_V(stc->msb_pts_shift   , tmp < 16);
+    stc->max_pts_distance= get_v(bc);
+    GET_V(stc->decode_delay    , tmp < 1000); //sanity limit, raise this if moors law is true
+    st->codec->has_b_frames= stc->decode_delay;
+    get_v(bc); //stream flags
+
+    GET_V(st->codec->extradata_size, tmp < (1<<30));
+    if(st->codec->extradata_size){
+        st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
+        get_buffer(bc, st->codec->extradata, st->codec->extradata_size);
+    }
+
+    if (st->codec->codec_type == CODEC_TYPE_VIDEO){
+        GET_V(st->codec->width , tmp > 0)
+        GET_V(st->codec->height, tmp > 0)
+        st->codec->sample_aspect_ratio.num= get_v(bc);
+        st->codec->sample_aspect_ratio.den= get_v(bc);
+        if((!st->codec->sample_aspect_ratio.num) != (!st->codec->sample_aspect_ratio.den)){
+            av_log(s, AV_LOG_ERROR, "invalid aspect ratio\n");
+            return -1;
+        }
+        get_v(bc); /* csp type */
+    }else if (st->codec->codec_type == CODEC_TYPE_AUDIO){
+        GET_V(st->codec->sample_rate , tmp > 0)
+        tmp= get_v(bc); // samplerate_den
+        if(tmp > st->codec->sample_rate){
+            av_log(s, AV_LOG_ERROR, "bleh, libnut muxed this ;)\n");
+            st->codec->sample_rate= tmp;
+        }
+        GET_V(st->codec->channels, tmp > 0)
+    }
+    if(skip_reserved(bc, end) || check_checksum(bc)){
+        av_log(s, AV_LOG_ERROR, "Stream header %d checksum mismatch\n", stream_id);
+        return -1;
+    }
+    stc->time_base= nut->time_base[stc->time_base_id];
+    av_set_pts_info(s->streams[stream_id], 63, stc->time_base.num, stc->time_base.den);
+    return 0;
+}
+
+static int decode_info_header(NUTContext *nut){
+    AVFormatContext *s= nut->avf;
+    ByteIOContext *bc = &s->pb;
+    uint64_t tmp;
+    unsigned int stream_id_plus1, chapter_start, chapter_len, count;
+    int chapter_id, i;
+    int64_t value, end;
+    char name[256], str_value[1024], type_str[256], *type= type_str;
+
+    end= get_packetheader(nut, bc, 1);
+    end += url_ftell(bc) - 4;
+
+    GET_V(stream_id_plus1, tmp <= s->nb_streams)
+    chapter_id   = get_s(bc);
+    chapter_start= get_v(bc);
+    chapter_len  = get_v(bc);
+    count        = get_v(bc);
+    for(i=0; i<count; i++){
+        get_str(bc, name, sizeof(name));
+        value= get_s(bc);
+        if(value == -1){
+            type= "UTF-8";
+            get_str(bc, str_value, sizeof(str_value));
+        }else if(value == -2){
+            get_str(bc, type, sizeof(type));
+            get_str(bc, str_value, sizeof(str_value));
+        }else if(value == -3){
+            type= "s";
+            value= get_s(bc);
+        }else if(value == -4){
+            type= "t";
+            value= get_v(bc);
+        }else if(value < -4){
+            type= "r";
+            get_s(bc);
+        }else{
+            type= "v";
+        }
+
+        if(chapter_id==0 && !strcmp(type, "UTF-8")){
+            if     (!strcmp(name, "Author"))
+                pstrcpy(s->author   , sizeof(s->author)   , str_value);
+            else if(!strcmp(name, "Title"))
+                pstrcpy(s->title    , sizeof(s->title)    , str_value);
+            else if(!strcmp(name, "Copyright"))
+                pstrcpy(s->copyright, sizeof(s->copyright), str_value);
+            else if(!strcmp(name, "Description"))
+                pstrcpy(s->comment  , sizeof(s->comment)  , str_value);
+        }
+    }
+
+    if(skip_reserved(bc, end) || check_checksum(bc)){
+        av_log(s, AV_LOG_ERROR, "Info header checksum mismatch\n");
+        return -1;
+    }
+    return 0;
+}
+
+static int decode_syncpoint(NUTContext *nut){
+    AVFormatContext *s= nut->avf;
+    ByteIOContext *bc = &s->pb;
+    int64_t end;
+    uint64_t tmp;
+    int i;
+    AVRational time_base;
+
+    nut->last_syncpoint_pos= url_ftell(bc);
+
+    end= get_packetheader(nut, bc, 1);
+    end += url_ftell(bc) - 4;
+
+    tmp= get_v(bc);
+    get_v(bc); //back_ptr_div16
+
+    time_base= nut->time_base[tmp % nut->time_base_count];
+    for(i=0; i<s->nb_streams; i++){
+        nut->stream[i].last_pts= av_rescale_q(tmp / nut->time_base_count, time_base, nut->stream[i].time_base); //FIXME rounding and co
+        //last_key_frame ?
+    }
+    //FIXME put this in a reset func maybe
+
+    if(skip_reserved(bc, end) || 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+1){
+            av_log(s, AV_LOG_ERROR, "no main startcode found\n");
+            return -1;
+        }
+        if(decode_main_header(nut) >= 0)
+            break;
+    }
+
+    /* stream headers */
+    pos=0;
+    for(inited_stream_count=0; inited_stream_count < s->nb_streams;){
+        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 == SYNCPOINT_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 *flags_ret, int64_t *pts, int *stream_id, int frame_code){
+    AVFormatContext *s= nut->avf;
+    ByteIOContext *bc = &s->pb;
+    StreamContext *stc;
+    int size, flags, size_mul, pts_delta, i, reserved_count;
+    uint64_t tmp;
+
+    if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
+        av_log(s, AV_LOG_ERROR, "last frame must have been damaged\n");
+        return -1;
+    }
+
+    flags          = nut->frame_code[frame_code].flags;
+    size_mul       = nut->frame_code[frame_code].size_mul;
+    size           = nut->frame_code[frame_code].size_lsb;
+    *stream_id     = nut->frame_code[frame_code].stream_id;
+    pts_delta      = nut->frame_code[frame_code].pts_delta;
+    reserved_count = nut->frame_code[frame_code].reserved_count;
+
+    if(flags & FLAG_INVALID)
+        return -1;
+    if(flags & FLAG_CODED)
+        flags ^= get_v(bc);
+    if(flags & FLAG_STREAM_ID){
+        GET_V(*stream_id, tmp < s->nb_streams)
+    }
+    stc= &nut->stream[*stream_id];
+    if(flags&FLAG_CODED_PTS){
+        int coded_pts= get_v(bc);
+//FIXME check last_pts validity?
+        if(coded_pts < (1<<stc->msb_pts_shift)){
+            *pts=lsb2full(stc, coded_pts);
+        }else
+            *pts=coded_pts - (1<<stc->msb_pts_shift);
+    }else
+        *pts= stc->last_pts + pts_delta;
+    if(flags&FLAG_SIZE_MSB){
+        size += size_mul*get_v(bc);
+    }
+    if(flags&FLAG_RESERVED)
+        reserved_count= get_v(bc);
+    for(i=0; i<reserved_count; i++)
+        get_v(bc);
+    if(flags&FLAG_CHECKSUM){
+        get_be32(bc); //FIXME check this
+    }
+    *flags_ret= flags;
+
+    stc->last_pts= *pts;
+    stc->last_key_frame= flags&FLAG_KEY; //FIXME change to last flags
+
+    return size;
+}
+
+static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
+    AVFormatContext *s= nut->avf;
+    ByteIOContext *bc = &s->pb;
+    int size, stream_id, flags, discard;
+    int64_t pts, last_IP_pts;
+
+    size= decode_frame_header(nut, &flags, &pts, &stream_id, frame_code);
+    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 && !(flags & FLAG_KEY))
+       ||(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 (flags & FLAG_KEY)
+        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, skip;
+
+    for(;;){
+        int64_t pos= url_ftell(bc);
+        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:
+            skip= get_packetheader(nut, bc, 0);
+            url_fseek(bc, skip, SEEK_CUR);
+            break;
+        case INFO_STARTCODE:
+            if(decode_info_header(nut)<0)
+                goto resync;
+            break;
+        case SYNCPOINT_STARTCODE:
+            if(decode_syncpoint(nut)<0)
+                goto resync;
+            frame_code = get_byte(bc);
+        case 0:
+            ret= decode_frame(nut, pkt, frame_code);
+            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", pos);
+            tmp= find_any_startcode(bc, pos+1);
+            if(tmp==0)
+                return -1;
+av_log(s, AV_LOG_DEBUG, "sync\n");
+            nut->next_startcode= tmp;
+        }
+    }
+}
+
+static int nut_read_close(AVFormatContext *s)
+{
+    NUTContext *nut = s->priv_data;
+
+    av_freep(&nut->time_base);
+    av_freep(&nut->stream);
+
+    return 0;
+}
+
+#ifdef CONFIG_NUT_DEMUXER
+AVInputFormat nut_demuxer = {
+    "nut",
+    "nut format",
+    sizeof(NUTContext),
+    nut_probe,
+    nut_read_header,
+    nut_read_packet,
+    nut_read_close,
+    NULL,
+    NULL,
+    .extensions = "nut",
+};
+#endif