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ffmpeg/libavformat/nutdec.c
Clemens Ladisch 559fd1e795 fix end-of-file detection 
At the end of a nut file, the check for url_feof() fails because the
eof flag was cleared by the url_fseek() call that was used to skip over
the index packet.    This patch fixes this
patch by: Clemens Ladisch % cladisch A fastmail P net %
Original thread:
Date: Feb 27, 2007 6:13 PM
Subject: [Ffmpeg-devel] [PATCH] nutdec: fix end-of-file detection

Originally committed as revision 8447 to svn://svn.ffmpeg.org/ffmpeg/trunk
2007-03-18 23:59:56 +00:00

886 lines
27 KiB
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/*
* "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 "tree.h"
#include "nut.h"
#undef NDEBUG
#include <assert.h>
static uint64_t get_v(ByteIOContext *bc){
uint64_t val = 0;
int tmp;
do{
tmp = get_byte(bc);
val= (val<<7) + (tmp&127);
}while(tmp&128);
return val;
}
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);
if(size > 4096)
get_be32(bc); //FIXME check this
init_checksum(bc, calculate_checksum ? av_crc04C11DB7_update : NULL, 0);
// nut->packet_start[2] = start;
// nut->written_packet_size= size;
return size;
}
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);
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) || get_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, stream_id;
uint64_t tmp, end;
AVStream *st;
end= get_packetheader(nut, bc, 1);
end += url_ftell(bc);
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) || get_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);
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) || get_checksum(bc)){
av_log(s, AV_LOG_ERROR, "Info header checksum mismatch\n");
return -1;
}
return 0;
}
int sp_pos_cmp(syncpoint_t *a, syncpoint_t *b){
return (a->pos - b->pos>>32) - (b->pos - a->pos>>32);
}
int sp_pts_cmp(syncpoint_t *a, syncpoint_t *b){
return (a->ts - b->ts>>32) - (b->ts - a->ts>>32);
}
static void add_sp(NUTContext *nut, int64_t pos, int64_t back_ptr, int64_t ts){
syncpoint_t *sp2, *sp= av_mallocz(sizeof(syncpoint_t));
sp->pos= pos;
sp->back_ptr= back_ptr;
sp->ts= ts;
sp2= av_tree_insert(&nut->syncpoints, sp, sp_pos_cmp);
if(sp2 && sp2 != sp)
av_free(sp);
}
static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
AVFormatContext *s= nut->avf;
ByteIOContext *bc = &s->pb;
int64_t end, tmp;
int i;
AVRational time_base;
nut->last_syncpoint_pos= url_ftell(bc)-8;
end= get_packetheader(nut, bc, 1);
end += url_ftell(bc);
tmp= get_v(bc);
*back_ptr= nut->last_syncpoint_pos - 16*get_v(bc);
if(*back_ptr < 0)
return -1;
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_rnd(
tmp / nut->time_base_count,
time_base.num * (int64_t)nut->stream[i].time_base.den,
time_base.den * (int64_t)nut->stream[i].time_base.num,
AV_ROUND_DOWN);
//last_key_frame ?
}
//FIXME put this in a reset func maybe
if(skip_reserved(bc, end) || get_checksum(bc)){
av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
return -1;
}
*ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
return 0;
}
static int find_and_decode_index(NUTContext *nut){
AVFormatContext *s= nut->avf;
ByteIOContext *bc = &s->pb;
uint64_t tmp, end;
int i, j, syncpoint_count;
int64_t filesize= url_fsize(bc);
int64_t *syncpoints;
int8_t *has_keyframe;
url_fseek(bc, filesize-12, SEEK_SET);
url_fseek(bc, filesize-get_be64(bc), SEEK_SET);
if(get_be64(bc) != INDEX_STARTCODE){
av_log(s, AV_LOG_ERROR, "no index at the end\n");
return -1;
}
end= get_packetheader(nut, bc, 1);
end += url_ftell(bc);
get_v(bc); //max_pts
GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
for(i=0; i<syncpoint_count; i++){
GET_V(syncpoints[i], tmp>0)
if(i)
syncpoints[i] += syncpoints[i-1];
}
for(i=0; i<s->nb_streams; i++){
int64_t last_pts= -1;
for(j=0; j<syncpoint_count;){
uint64_t x= get_v(bc);
int type= x&1;
int n= j;
x>>=1;
if(type){
int flag= x&1;
x>>=1;
if(n+x >= syncpoint_count + 1){
av_log(s, AV_LOG_ERROR, "index overflow A\n");
return -1;
}
while(x--)
has_keyframe[n++]= flag;
has_keyframe[n++]= !flag;
}else{
while(x != 1){
if(n>=syncpoint_count + 1){
av_log(s, AV_LOG_ERROR, "index overflow B\n");
return -1;
}
has_keyframe[n++]= x&1;
x>>=1;
}
}
if(has_keyframe[0]){
av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
return -1;
}
assert(n<=syncpoint_count+1);
for(; j<n; j++){
if(has_keyframe[j]){
uint64_t B, A= get_v(bc);
if(!A){
A= get_v(bc);
B= get_v(bc);
//eor_pts[j][i] = last_pts + A + B
}else
B= 0;
av_add_index_entry(
s->streams[i],
16*syncpoints[j-1],
last_pts + A,
0,
0,
AVINDEX_KEYFRAME);
last_pts += A + B;
}
}
}
}
if(skip_reserved(bc, end) || get_checksum(bc)){
av_log(s, AV_LOG_ERROR, "Index 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;
do{
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;
}
}while(decode_main_header(nut) < 0);
/* 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);
}
s->data_offset= pos-8;
if(!url_is_streamed(bc)){
int64_t orig_pos= url_ftell(bc);
find_and_decode_index(nut);
url_fseek(bc, orig_pos, SEEK_SET);
}
assert(nut->next_startcode == SYNCPOINT_STARTCODE);
return 0;
}
static int decode_frame_header(NUTContext *nut, 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 %Ld > %Ld + %d\n", url_ftell(bc), nut->last_syncpoint_pos, nut->max_distance);
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
}else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
return -1;
}
stc->last_pts= *pts;
stc->last_flags= 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, discard;
int64_t pts, last_IP_pts;
StreamContext *stc;
size= decode_frame_header(nut, &pts, &stream_id, frame_code);
if(size < 0)
return -1;
stc= &nut->stream[stream_id];
if (stc->last_flags & FLAG_KEY)
stc->skip_until_key_frame=0;
discard= s->streams[ stream_id ]->discard;
last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
if( (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
|| discard >= AVDISCARD_ALL
|| stc->skip_until_key_frame){
url_fskip(bc, size);
return 1;
}
av_get_packet(bc, pkt, size);
pkt->stream_index = stream_id;
if (stc->last_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;
int64_t ts, back_ptr;
for(;;){
int64_t pos= url_ftell(bc);
uint64_t tmp= nut->next_startcode;
nut->next_startcode=0;
if(tmp){
pos-=8;
}else{
frame_code = get_byte(bc);
if(url_feof(bc))
return -1;
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, &ts, &back_ptr)<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, nut->last_syncpoint_pos+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;
ByteIOContext *bc = &s->pb;
int64_t pos, pts, back_ptr;
av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
pos= *pos_arg;
resync:
do{
pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
if(pos < 1){
assert(nut->next_startcode == 0);
av_log(s, AV_LOG_ERROR, "read_timestamp failed\n");
return AV_NOPTS_VALUE;
}
}while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
*pos_arg = pos-1;
assert(nut->last_syncpoint_pos == *pos_arg);
av_log(s, AV_LOG_DEBUG, "return %Ld %Ld\n", pts,back_ptr );
if (stream_index == -1) return pts;
else if(stream_index == -2) return back_ptr;
assert(0);
}
static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
NUTContext *nut = s->priv_data;
AVStream *st= s->streams[stream_index];
syncpoint_t dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
syncpoint_t nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
syncpoint_t *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
int64_t pos, pos2, ts;
int i;
if(st->index_entries){
int index= av_index_search_timestamp(st, pts, flags);
if(index<0)
return -1;
pos2= st->index_entries[index].pos;
ts = st->index_entries[index].timestamp;
}else{
av_tree_find(nut->syncpoints, &dummy, sp_pts_cmp, next_node);
av_log(s, AV_LOG_DEBUG, "%Ld-%Ld %Ld-%Ld\n", next_node[0]->pos, next_node[1]->pos,
next_node[0]->ts , next_node[1]->ts);
pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
if(!(flags & AVSEEK_FLAG_BACKWARD)){
dummy.pos= pos+16;
next_node[1]= &nopts_sp;
av_tree_find(nut->syncpoints, &dummy, sp_pos_cmp, next_node);
pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos , next_node[1]->pos, next_node[1]->pos,
next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
if(pos2>=0)
pos= pos2;
//FIXME dir but i think it doesnt matter
}
dummy.pos= pos;
sp= av_tree_find(nut->syncpoints, &dummy, sp_pos_cmp, NULL);
assert(sp);
pos2= sp->back_ptr - 15;
}
av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
pos= find_startcode(&s->pb, SYNCPOINT_STARTCODE, pos2);
url_fseek(&s->pb, pos, SEEK_SET);
av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
if(pos2 > pos || pos2 + 15 < pos){
av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
}
for(i=0; i<s->nb_streams; i++)
nut->stream[i].skip_until_key_frame=1;
return 0;
}
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,
read_seek,
.extensions = "nut",
};
#endif
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