July 30, 2020 1:08 AM, "Andreas Rheinhardt" <andreas.rheinha...@gmail.com> wrote:
> Anamitra Ghorui: > >> This patch implements non interlaced decoding of FLIF16 images with all >> transforms except for one, FrameLookback which is being tested. >> >> Several test files have been attached. The above mentioned transform >> and interlaced decoding is being tested and will be implemented shortly. >> >> The main reason of posting this patch now is to ask advice on deflate >> decompression (or inflate) on the metadata segments of the format. >> The reference decoder of the format [1] uses lodepng, and by extension, >> deflate for generating the metadata segments. Therefore these segments >> should be able to be decoded by zlib's deflate routines. However it does >> not work and returns saying that the data is invalid. >> I have tried isolating the metadata using a hex editor, and then using >> zlib's example program [2] to decode it. However it also says that it's >> invalid data. >> Can you please tell me what I am doing wrong in libavformat/flifdec.c? >> >> [1]: https://github.com/FLIF-hub/FLIF >> [2]: https://zlib.net/zpipe.c >> >> Co-authored-by: Anamitra Ghorui <agho...@teknik.io> >> Co-authored-by: Karhtik K. Khullar <kartikkhullar...@gmail.com> >> >> Signed-off-by: Anamitra Ghorui <agho...@teknik.io> >> --- > > [...] > >> + >> +#if 0 >> +// CONFIG_ZLIB >> +static int flif_inflate(FLIFDemuxContext *s, unsigned char *buf, int >> buf_size, >> + unsigned char *out_buf, int *out_buf_size) > > I did not look thoroughly at it at all, but this is already wrong: > flif_inflate allocates out_buf and in order to return it, the parameter > must be of type unsigned char ** (or uint8_t ** (that is preferred here)). > Yes, A pretty bad blunder. Will post a new patch for it soon. I have tried replacing the metadata segment (after fixing the above errors) in the encoded file with dummy data from zpipe.c [1] and the function decodes the dummy data properly. So I am guessing that maybe I am not setting the proper parameters somewhere. I have tried using different flushes (Z_PARTIAL_FLUSH, Z_NO_FLUSH etc.) but it did not work. [1]: https://zlib.net/zpipe.c Regards, Anamitra _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
