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mlpdec: Don't overallocate buffers.

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Now that max channels and primitive matrices are properly validated, there is
no need to be paranoid that random data will be overwritten.
As a bonus this makes matrix_coeff 16-byte aligned between matrices.

Originally committed as revision 18651 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Ramiro Polla 2009-04-21 22:53:46 +00:00
parent 309616b249
commit 420df93037
2 changed files with 8 additions and 5 deletions
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9
libavcodec/mlp.h
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@ -29,15 +29,18 @@
/** Last possible matrix channel for each codec */
#define MAX_MATRIX_CHANNEL_MLP 5
#define MAX_MATRIX_CHANNEL_TRUEHD 7
/** Maximum number of channels that can be decoded. */
#define MAX_CHANNELS 16
/** Maximum number of channels in a valid stream.
* MLP : 5.1 + 2 noise channels -> 8 channels
* TrueHD: 7.1 -> 8 channels
*/
#define MAX_CHANNELS 8
/** Maximum number of matrices used in decoding; most streams have one matrix
* per output channel, but some rematrix a channel (usually 0) more than once.
*/
#define MAX_MATRICES_MLP 6
#define MAX_MATRICES_TRUEHD 8
#define MAX_MATRICES 15
#define MAX_MATRICES 8
/** Maximum number of substreams that can be decoded.
* MLP's limit is 2. TrueHD supports at least up to 3.

4
libavcodec/mlpdec.c
View File

@ -93,7 +93,7 @@ typedef struct SubStream {
//! Whether the LSBs of the matrix output are encoded in the bitstream.
uint8_t lsb_bypass[MAX_MATRICES];
//! Matrix coefficients, stored as 2.14 fixed point.
int32_t matrix_coeff[MAX_MATRICES][MAX_CHANNELS+2];
int32_t matrix_coeff[MAX_MATRICES][MAX_CHANNELS];
//! Left shift to apply to noise values in 0x31eb substreams.
uint8_t matrix_noise_shift[MAX_MATRICES];
//@}
@ -143,7 +143,7 @@ typedef struct MLPDecodeContext {
int8_t noise_buffer[MAX_BLOCKSIZE_POW2];
int8_t bypassed_lsbs[MAX_BLOCKSIZE][MAX_CHANNELS];
int32_t sample_buffer[MAX_BLOCKSIZE][MAX_CHANNELS+2];
int32_t sample_buffer[MAX_BLOCKSIZE][MAX_CHANNELS];
} MLPDecodeContext;
static VLC huff_vlc[3];