[FFmpeg-devel,3/5] aptx: do some clipping to match original codec in extreme cases

Submitted by Aurelien Jacobs on Jan. 6, 2018, 4:48 p.m.

Details

Message ID 20180106164808.26162-4-aurel@gnuage.org
State New
Headers show

Commit Message

Aurelien Jacobs Jan. 6, 2018, 4:48 p.m.
---
 libavcodec/aptx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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diff --git a/libavcodec/aptx.c b/libavcodec/aptx.c
index 64a63a7d5b..4173402d03 100644
--- a/libavcodec/aptx.c
+++ b/libavcodec/aptx.c
@@ -466,6 +466,7 @@  static void aptx_quantize_difference(Quantize *quantize,
     int64_t error;
 
     sample_difference_abs = FFABS(sample_difference);
+    sample_difference_abs = FFMIN(sample_difference_abs, (1 << 23) - 1);
 
     quantized_sample = aptx_bin_search(sample_difference_abs >> 4,
                                        quantization_factor,
@@ -478,7 +479,7 @@  static void aptx_quantize_difference(Quantize *quantize,
     mean = (intervals[1] + intervals[0]) / 2;
     interval = (intervals[1] - intervals[0]) * (-(sample_difference < 0) | 1);
 
-    dithered_sample = rshift64_clip24(MUL64(dither, interval) + ((int64_t)(mean + d) << 32), 32);
+    dithered_sample = rshift64_clip24(MUL64(dither, interval) + ((int64_t)av_clip_intp2(mean + d, 23) << 32), 32);
     error = ((int64_t)sample_difference_abs << 20) - MUL64(dithered_sample, quantization_factor);
     quantize->error = FFABS(rshift64(error, 23));