On Wed, Apr 01, 2015 at 01:17:50PM +0000, Donny Yang wrote: > On 1 April 2015 at 23:28, Michael Niedermayer <michae...@gmx.at> wrote: > > > On Wed, Apr 01, 2015 at 12:07:46PM +0000, Donny Yang wrote: > > > On 1 April 2015 at 22:57, Paul B Mahol <one...@gmail.com> wrote: > > > > > > > On 4/1/15, Donny Yang <w...@kota.moe> wrote: > > > > > On 1 April 2015 at 17:03, Paul B Mahol <one...@gmail.com> wrote: > > > > > > > > > >> Dana 31. 3. 2015. 22:59 osoba "Donny Yang" <w...@kota.moe> > > napisala je: > > > > >> > +#include <zlib.h> > > > > >> > > > > >> This is missing dependency on zlib in configure. > > > > >> > > > > > Fixed > > > > > > > > > > > > > > > > > > But this is more appropriate for APNG encoder. APNG muxer seems to not > > > > use zlib at all. > > > > > > > It's used for it's crc32 functions for editing/creating chunks. > > > > please use libavutil/crc* > > > > I applied the following patch to my code, but ffmpeg's functions seem to be > producing the wrong crc32 value. > > For example: > $ crc32 <(printf "acTL\x00\x00\x00\x14\x00\x00\x00\x00") > 1c2df152 > While a `av_crc(av_crc_get_table(AV_CRC_32_IEEE), 0, > "acTL\x00\x00\x00\x14\x00\x00\x00\x00", 12)` returns 0xf6f7ccdd. > (using AV_CRC_32_IEEE_LE also produces an incorrect checksum) > > What am I doing wrong?
http://www.w3.org/TR/PNG-CRCAppendix.html says: /* Update a running CRC with the bytes buf[0..len-1]--the CRC should be initialized to all 1's, and the transmitted value is the 1's complement of the final running CRC (see the crc() routine below)). */ [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB No great genius has ever existed without some touch of madness. -- Aristotle
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