Bug#762571: Debdiff
Martin Steghöfer
martin at steghoefer.eu
Wed Oct 1 11:02:41 UTC 2014
Petter Reinholdtsen wrote:
> Do you have a working patch you can append to this bug?
Here you go, that's what fixed the issue for me (attached debdiff).
Disclaimer: Not sure, if I did the debdiff 100% correct, libvorbis uses
source format 1.0 and I've never worked with non-quilt packages before.
I haven't done much testing of the patched library, either (I'm not a
regular user of libvorbis).
Cheers,
Martin
-------------- next part --------------
diff -u libvorbis-1.3.2/debian/changelog libvorbis-1.3.2/debian/changelog
--- libvorbis-1.3.2/debian/changelog
+++ libvorbis-1.3.2/debian/changelog
@@ -1,3 +1,11 @@
+libvorbis (1.3.2-1.5) UNRELEASED; urgency=medium
+
+ * Non-maintainer upload.
+ * Fix problems with seeking to PCM 0 by backporting r19159 of
+ upstream SVN, authored by Chris Montgomery. (Closes: #762571)
+
+ -- Martin Steghöfer <martin at steghoefer.eu> Wed, 01 Oct 2014 12:36:56 +0200
+
libvorbis (1.3.2-1.4) unstable; urgency=low
* Non-maintainer upload.
only in patch2:
unchanged:
--- libvorbis-1.3.2.orig/lib/vorbisfile.c
+++ libvorbis-1.3.2/lib/vorbisfile.c
@@ -1417,22 +1417,28 @@
if(pos>=total)break;
}
- /* search within the logical bitstream for the page with the highest
- pcm_pos preceding (or equal to) pos. There is a danger here;
- missing pages or incorrect frame number information in the
- bitstream could make our task impossible. Account for that (it
- would be an error condition) */
+ /* Search within the logical bitstream for the page with the highest
+ pcm_pos preceding pos. If we're looking for a position on the
+ first page, bisection will halt without finding our position as
+ it's before the first explicit granulepos fencepost. That case is
+ handled separately below.
+
+ There is a danger here; missing pages or incorrect frame number
+ information in the bitstream could make our task impossible.
+ Account for that (it would be an error condition) */
+
+ /* new search algorithm originally by HB (Nicholas Vinen) */
- /* new search algorithm by HB (Nicholas Vinen) */
{
ogg_int64_t end=vf->offsets[link+1];
- ogg_int64_t begin=vf->offsets[link];
+ ogg_int64_t begin=vf->dataoffsets[link];
ogg_int64_t begintime = vf->pcmlengths[link*2];
ogg_int64_t endtime = vf->pcmlengths[link*2+1]+begintime;
ogg_int64_t target=pos-total+begintime;
- ogg_int64_t best=begin;
+ ogg_int64_t best=-1;
ogg_page og;
+ /* bisection loop */
while(begin<end){
ogg_int64_t bisect;
@@ -1447,51 +1453,82 @@
bisect=begin;
}
+ /* only seek if the file position isn't already there */
if(bisect!=vf->offset){
result=_seek_helper(vf,bisect);
if(result) goto seek_error;
}
+ /* read loop within the bisection loop */
while(begin<end){
result=_get_next_page(vf,&og,end-vf->offset);
if(result==OV_EREAD) goto seek_error;
if(result<0){
+ /* there is no next page! */
if(bisect<=begin+1)
- end=begin; /* found it */
+ /* No bisection left to perform. We've either found the
+ best candidate already or failed. Exit loop. */
+ end=begin;
else{
+ /* We tried to load a fraction of the last page; back up a
+ bit and try to get the whole last page */
if(bisect==0) goto seek_error;
bisect-=CHUNKSIZE;
+
+ /* don't repeat/loop on a read we've already performed */
if(bisect<=begin)bisect=begin+1;
+
+ /* seek and cntinue bisection */
result=_seek_helper(vf,bisect);
if(result) goto seek_error;
}
}else{
ogg_int64_t granulepos;
+ /* got a page. analyze it */
+ /* only consider pages from primary vorbis stream */
if(ogg_page_serialno(&og)!=vf->serialnos[link])
continue;
+ /* only consider pages with the granulepos set */
granulepos=ogg_page_granulepos(&og);
if(granulepos==-1)continue;
if(granulepos<target){
+ /* this page is a successful candidate! Set state */
+
best=result; /* raw offset of packet with granulepos */
begin=vf->offset; /* raw offset of next page */
begintime=granulepos;
+ /* if we're before our target but within a short distance,
+ don't bisect; read forward */
if(target-begintime>44100)break;
- bisect=begin; /* *not* begin + 1 */
+
+ bisect=begin; /* *not* begin + 1 as above */
}else{
- if(bisect<=begin+1)
- end=begin; /* found it */
- else{
- if(end==vf->offset){ /* we're pretty close - we'd be stuck in */
+
+ /* This is one of our pages, but the granpos is
+ post-target; it is not a bisection return
+ candidate. (The only way we'd use it is if it's the
+ first page in the stream; we handle that case later
+ outside the bisection) */
+ if(bisect<=begin+1){
+ /* No bisection left to perform. We've either found the
+ best candidate already or failed. Exit loop. */
+ end=begin;
+ }else{
+ if(end==vf->offset){
+ /* bisection read to the end; use the known page
+ boundary (result) to update bisection, back up a
+ little bit, and try again */
end=result;
- bisect-=CHUNKSIZE; /* an endless loop otherwise. */
+ bisect-=CHUNKSIZE;
if(bisect<=begin)bisect=begin+1;
result=_seek_helper(vf,bisect);
if(result) goto seek_error;
}else{
+ /* Normal bisection */
end=bisect;
endtime=granulepos;
break;
@@ -1502,9 +1539,46 @@
}
}
- /* found our page. seek to it, update pcm offset. Easier case than
- raw_seek, don't keep packets preceding granulepos. */
- {
+ /* Out of bisection: did it 'fail?' */
+ if(best == -1){
+
+ /* Check the 'looking for data in first page' special case;
+ bisection would 'fail' because our search target was before the
+ first PCM granule position fencepost. */
+
+ if(begin == vf->dataoffsets[link] &&
+ ogg_page_serialno(&og)==vf->serialnos[link]){
+
+ /* Yes, this is the beginning-of-stream case. We already have
+ our page, right at the beginning of PCM data. Set state
+ and return. */
+
+ vf->offset=result;
+ vf->pcm_offset=total;
+
+ if(link!=vf->current_link){
+ /* Different link; dump entire decode machine */
+ _decode_clear(vf);
+
+ vf->current_link=link;
+ vf->current_serialno=vf->serialnos[link];
+ vf->ready_state=STREAMSET;
+
+ }else{
+ vorbis_synthesis_restart(&vf->vd);
+ }
+
+ ogg_stream_reset_serialno(&vf->os,vf->current_serialno);
+ ogg_stream_pagein(&vf->os,&og);
+
+ }else
+ goto seek_error;
+
+ }else{
+
+ /* Bisection found our page. seek to it, update pcm offset. Easier case than
+ raw_seek, don't keep packets preceding granulepos. */
+
ogg_page og;
ogg_packet op;
@@ -1534,15 +1608,19 @@
while(1){
result=ogg_stream_packetpeek(&vf->os,&op);
if(result==0){
- /* !!! the packet finishing this page originated on a
- preceding page. Keep fetching previous pages until we
- get one with a granulepos or without the 'continued' flag
- set. Then just use raw_seek for simplicity. */
+ /* No packet returned; we exited the bisection with 'best'
+ pointing to a page with a granule position, so the packet
+ finishing this page ('best') originated on a preceding
+ page. Keep fetching previous pages until we get one with
+ a granulepos or without the 'continued' flag set. Then
+ just use raw_seek for simplicity. */
result=_seek_helper(vf,best);
if(result<0) goto seek_error;
- while(1){
+ /* Do not rewind past the beginning of link data; if we do,
+ it's either a bug or a broken stream */
+ while(result>vf->dataoffsets[link]){
result=_get_prev_page(vf,&og);
if(result<0) goto seek_error;
if(ogg_page_serialno(&og)==vf->current_serialno &&
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