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stb_vorbis: fix seeking in files with audio packets in header pages

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Fixes #682, #580
This commit is contained in:
Dougall Johnson 2019-10-01 20:47:29 +10:00
parent 2abc5c6ced
commit 7c4eb44a63
1 changed files with 20 additions and 7 deletions
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25
stb_vorbis.c
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@ -774,8 +774,11 @@ struct stb_vorbis
uint8 push_mode;
// the page to seek to when seeking to start, may be zero
uint32 first_audio_page_offset;
// p_first is the page on which the first audio packet ends
// (but not necessarily the page on which it starts)
ProbedPage p_first, p_last;
// memory management
@ -1404,6 +1407,9 @@ static int capture_pattern(vorb *f)
static int start_page_no_capturepattern(vorb *f)
{
uint32 loc0,loc1,n;
if (f->first_decode && !IS_PUSH_MODE(f)) {
f->p_first.page_start = stb_vorbis_get_file_offset(f) - 4;
}
// stream structure version
if (0 != get8(f)) return error(f, VORBIS_invalid_stream_structure_version);
// header flag
@ -1440,15 +1446,12 @@ static int start_page_no_capturepattern(vorb *f)
}
if (f->first_decode) {
int i,len;
ProbedPage p;
len = 0;
for (i=0; i < f->segment_count; ++i)
len += f->segments[i];
len += 27 + f->segment_count;
p.page_start = f->first_audio_page_offset;
p.page_end = p.page_start + len;
p.last_decoded_sample = loc0;
f->p_first = p;
f->p_first.page_end = f->p_first.page_start + len;
f->p_first.last_decoded_sample = loc0;
}
f->next_seg = 0;
return TRUE;
@ -3576,6 +3579,7 @@ static int start_decoder(vorb *f)
int longest_floorlist=0;
// first page, first packet
f->first_decode = TRUE;
if (!start_page(f)) return FALSE;
// validate page flag
@ -4132,7 +4136,6 @@ static int start_decoder(vorb *f)
f->temp_memory_required = imdct_mem;
}
f->first_decode = TRUE;
if (f->alloc.alloc_buffer) {
assert(f->temp_offset == f->alloc.alloc_buffer_length_in_bytes);
@ -4141,7 +4144,17 @@ static int start_decoder(vorb *f)
return error(f, VORBIS_outofmem);
}
// @TODO: stb_vorbis_seek_start expects first_audio_page_offset to point to a page
// without PAGEFLAG_continued_packet, so this either points to the first page, or
// the page after the end of the headers. It might be cleaner to point to a page
// in the middle of the headers, when that's the page where the first audio packet
// starts, but we'd have to also correctly skip the end of any continued packet in
// stb_vorbis_seek_start.
if (f->next_seg == -1) {
f->first_audio_page_offset = stb_vorbis_get_file_offset(f);
} else {
f->first_audio_page_offset = 0;
}
return TRUE;
}