ffmpeg | branch: master | Niklas Haas <[email protected]> | Sun Sep 12 15:14:31 2021 +0200| [52c35d648c29bc5f11372740d89e418e297ecd82] | committer: James Almer
avcodec/h274: don't read from uninitialized array members This bug flew under the radar because, in practice, these values are 0-initialized for the first invocation. But for subsequent invocations (with different h/v values), reading from the uninitialized parts of `out` is undefined behavior. Avoid this by simply adjusting the iteration range of the following loops. Has the added benefit of being a minor speedup. Signed-off-by: James Almer <[email protected]> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=52c35d648c29bc5f11372740d89e418e297ecd82 --- libavcodec/h274.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/libavcodec/h274.c b/libavcodec/h274.c index 5e2cf150ea..781878d7ad 100644 --- a/libavcodec/h274.c +++ b/libavcodec/h274.c @@ -74,9 +74,9 @@ static void init_slice_c(int8_t out[64][64], uint8_t h, uint8_t v, // 64x64 inverse integer transform for (int y = 0; y < 64; y++) { - for (int x = 0; x < 64; x++) { + for (int x = 0; x <= freq_h; x++) { int32_t sum = 0; - for (int p = 0; p < 64; p++) + for (int p = 0; p <= freq_v; p++) sum += R64T[y][p] * out[x][p]; tmp[y][x] = (sum + 128) >> 8; } @@ -85,7 +85,7 @@ static void init_slice_c(int8_t out[64][64], uint8_t h, uint8_t v, for (int y = 0; y < 64; y++) { for (int x = 0; x < 64; x++) { int32_t sum = 0; - for (int p = 0; p < 64; p++) + for (int p = 0; p <= freq_h; p++) sum += tmp[y][p] * R64T[x][p]; // R64T^T = R64 // Renormalize and clip to [-127, 127] out[y][x] = av_clip((sum + 128) >> 8, -127, 127); _______________________________________________ ffmpeg-cvslog mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
