On Thu, May 07, 2015 at 04:17:10PM +0100, Tom Butterworth wrote:
> Image dimensions were rounded down causing rows to wrap early if dimensions
> were not a multiple of 4.
> ---
> libavcodec/s3tc.c | 23 +++++++++++++----------
> 1 file changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/libavcodec/s3tc.c b/libavcodec/s3tc.c
> index 4743d78..9886b1d 100644
> --- a/libavcodec/s3tc.c
> +++ b/libavcodec/s3tc.c
> @@ -26,6 +26,7 @@
> #include "s3tc.h"
>
> static inline void dxt1_decode_pixels(GetByteContext *gb, uint32_t *d,
> + unsigned int w, unsigned int h,
> unsigned int qstride, unsigned int
> flag,
> uint64_t alpha) {
> unsigned int x, y, c0, c1, a = (!flag * 255u) << 24;
> @@ -62,14 +63,16 @@ static inline void dxt1_decode_pixels(GetByteContext *gb,
> uint32_t *d,
> colors[2] = rb2 + g2 + a;
>
> pixels = bytestream2_get_le32(gb);
> - for (y=0; y<4; y++) {
> - for (x=0; x<4; x++) {
> + for (y=0; y<h; y++) {
> + for (x=0; x<w; x++) {
> a = (alpha & 0x0f) << 28;
> a += a >> 4;
> d[x] = a + colors[pixels&3];
> pixels >>= 2;
> alpha >>= 4;
> }
> + for (; x<4; x++)
> + pixels >>= 2;
> d += qstride;
> }
> }
> @@ -77,21 +80,21 @@ static inline void dxt1_decode_pixels(GetByteContext *gb,
> uint32_t *d,
> void ff_decode_dxt1(GetByteContext *gb, uint8_t *dst,
> const unsigned int w, const unsigned int h,
> const unsigned int stride) {
> - unsigned int bx, by, qstride = stride/4;
> + unsigned int x, y, qstride = stride/4;
> uint32_t *d = (uint32_t *) dst;
>
> - for (by=0; by < h/4; by++, d += stride-w)
> - for (bx = 0; bx < w / 4; bx++, d += 4)
> - dxt1_decode_pixels(gb, d, qstride, 0, 0LL);
> + for (y=0; y < h; y += 4, d += stride-w)
> + for (x = 0; x < w; d += FFMIN(4, w-x), x += 4)
> + dxt1_decode_pixels(gb, d, FFMIN(4, w-x), FFMIN(4, h-y), qstride,
> 0, 0LL);
> }
please dont rename variables in patches which contain functional
changes
also, can you share the sample that this patch fixes decoding for ?
Thanks
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Good people do not need laws to tell them to act responsibly, while bad
people will find a way around the laws. -- Plato
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