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| author | Niklas Haas <git@haasn.dev> | 2021-09-12 15:14:31 +0200 |
|---|---|---|
| committer | James Almer <jamrial@gmail.com> | 2021-09-12 11:07:40 -0300 |
| commit | 52c35d648c29bc5f11372740d89e418e297ecd82 (patch) | |
| tree | f179d6472adfd4e9134ed1caa1cb9743df45c25d /libavcodec/h274.c | |
| parent | c4973e2148b03210c887496aa2b2ffd8b1ab6319 (diff) | |
| download | ffmpeg-52c35d648c29bc5f11372740d89e418e297ecd82.tar.gz | |
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 <jamrial@gmail.com>
Diffstat (limited to 'libavcodec/h274.c')
| -rw-r--r-- | libavcodec/h274.c | 6 |
1 files 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); |