/**
* Decode the group of blocks header or slice header.
* @return <0 if an error occurred
*/
static int h263_decode_gob_header(MpegEncContext *s)
{
unsigned int val, gob_number;
int left;
/* Check for GOB Start Code */
val = show_bits(&s->gb, 16);
if(val)
return -1;
/* We have a GBSC probably with GSTUFF */
skip_bits(&s->gb, 16); /* Drop the zeros */
left= get_bits_left(&s->gb);
left = FFMIN(left, 32);
//MN: we must check the bits left or we might end in a infinite loop (or segfault)
for(;left>13; left--){
if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
}
if(left<=13)
return -1;
if(s->h263_slice_structured){
if(check_marker(&s->gb, "before MBA")==0)
return -1;
ff_h263_decode_mba(s);
if(s->mb_num > 1583)
if(check_marker(&s->gb, "after MBA")==0)
return -1;
s->qscale = get_bits(&s->gb, 5); /* SQUANT */
if(check_marker(&s->gb, "after SQUANT")==0)
return -1;
skip_bits(&s->gb, 2); /* GFID */
}else{
gob_number = get_bits(&s->gb, 5); /* GN */
s->mb_x= 0;
s->mb_y= s->gob_index* gob_number;
skip_bits(&s->gb, 2); /* GFID */
s->qscale = get_bits(&s->gb, 5); /* GQUANT */
}
if(s->mb_y >= s->mb_height)
return -1;
if(s->qscale==0)
return -1;
return 0;
}
/* don't understand why they choose a different header ! */
int ff_intel_h263_decode_picture_header(MpegEncContext *s)
{
int format;
if (get_bits_left(&s->gb) == 64) { /* special dummy frames */
return FRAME_SKIPPED;
}
/* picture header */
if (get_bits_long(&s->gb, 22) != 0x20) {
av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
return -1;
}
s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
if (check_marker(&s->gb, "after picture_number") != 1) {
return -1; /* marker */
}
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
return -1; /* h263 id */
}
skip_bits1(&s->gb); /* split screen off */
skip_bits1(&s->gb); /* camera off */
skip_bits1(&s->gb); /* freeze picture release off */
format = get_bits(&s->gb, 3);
if (format == 0 || format == 6) {
av_log(s->avctx, AV_LOG_ERROR, "Intel H263 free format not supported\n");
return -1;
}
s->h263_plus = 0;
s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
s->h263_long_vectors = get_bits1(&s->gb);
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n");
return -1; /* SAC: off */
}
s->obmc= get_bits1(&s->gb);
s->unrestricted_mv = s->obmc || s->h263_long_vectors;
s->pb_frame = get_bits1(&s->gb);
if (format < 6) {
s->width = ff_h263_format[format][0];
s->height = ff_h263_format[format][1];
s->avctx->sample_aspect_ratio.num = 12;
s->avctx->sample_aspect_ratio.den = 11;
} else {
format = get_bits(&s->gb, 3);
if(format == 0 || format == 7){
av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H263 format\n");
return -1;
}
if(get_bits(&s->gb, 2))
av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
s->loop_filter = get_bits1(&s->gb) * !s->avctx->lowres;
if(get_bits1(&s->gb))
av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
if(get_bits1(&s->gb))
s->pb_frame = 2;
if(get_bits(&s->gb, 5))
av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
if(get_bits(&s->gb, 5) != 1)
av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n");
}
if(format == 6){
int ar = get_bits(&s->gb, 4);
skip_bits(&s->gb, 9); // display width
check_marker(&s->gb, "in dimensions");
skip_bits(&s->gb, 9); // display height
if(ar == 15){
s->avctx->sample_aspect_ratio.num = get_bits(&s->gb, 8); // aspect ratio - width
s->avctx->sample_aspect_ratio.den = get_bits(&s->gb, 8); // aspect ratio - height
} else {
s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[ar];
}
if (s->avctx->sample_aspect_ratio.num == 0)
av_log(s->avctx, AV_LOG_ERROR, "Invalid aspect ratio.\n");
}
s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
if(s->pb_frame){
skip_bits(&s->gb, 3); //temporal reference for B-frame
skip_bits(&s->gb, 2); //dbquant
}
/* PEI */
if (skip_1stop_8data_bits(&s->gb) < 0)
return AVERROR_INVALIDDATA;
s->f_code = 1;
s->y_dc_scale_table=
s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
ff_h263_show_pict_info(s);
return 0;
}
static void fb_spawn_teleport_destination_touch (void)
{
if (IsMarkerFrame() && other->ct == ctPlayer) {
check_marker (self, other);
}
}
