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| author | Thilo Borgmann <thilo.borgmann@googlemail.com> | 2010-02-16 14:48:01 +0000 |
|---|---|---|
| committer | Thilo Borgmann <thilo.borgmann@googlemail.com> | 2010-02-16 14:48:01 +0000 |
| commit | 114315994bc08812eeef51eaace455d86b5098d5 (patch) | |
| tree | fbb4a59a452e7c10732389305e03ddb9d03ef622 | |
| parent | 85207e38dc25b8452df231885ea1ade52e3bf19f (diff) | |
Limit the Rice parameter used for progressive decoding in ALS.
Originally committed as revision 21849 to svn://svn.ffmpeg.org/ffmpeg/trunk
| -rw-r--r-- | libavcodec/alsdec.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c index c00c57afa0..b9a22850cb 100644 --- a/libavcodec/alsdec.c +++ b/libavcodec/alsdec.c @@ -192,6 +192,7 @@ typedef struct { unsigned int frame_id; ///< the frame ID / number of the current frame unsigned int js_switch; ///< if true, joint-stereo decoding is enforced unsigned int num_blocks; ///< number of blocks used in the current frame + unsigned int s_max; ///< maximum Rice parameter allowed in entropy coding uint8_t *bgmc_lut; ///< pointer at lookup tables used for BGMC unsigned int *bgmc_lut_status; ///< pointer at lookup table status flags used for BGMC int ltp_lag_length; ///< number of bits used for ltp lag value @@ -720,9 +721,9 @@ static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd) if (opt_order) bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4); if (opt_order > 1) - bd->raw_samples[1] = decode_rice(gb, s[0] + 3); + bd->raw_samples[1] = decode_rice(gb, FFMIN(s[0] + 3, ctx->s_max)); if (opt_order > 2) - bd->raw_samples[2] = decode_rice(gb, s[0] + 1); + bd->raw_samples[2] = decode_rice(gb, FFMIN(s[0] + 1, ctx->s_max)); start = FFMIN(opt_order, 3); } @@ -1508,6 +1509,11 @@ static av_cold int decode_init(AVCodecContext *avctx) avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8; } + // set maximum Rice parameter for progressive decoding based on resolution + // This is not specified in 14496-3 but actually done by the reference + // codec RM22 revision 2. + ctx->s_max = sconf->resolution > 1 ? 31 : 15; + // set lag value for long-term prediction ctx->ltp_lag_length = 8 + (avctx->sample_rate >= 96000) + (avctx->sample_rate >= 192000); |