overlay_vulkan: add support for overlaying images with an alpha channel

[ffmpeg] / libavcodec / apedec.c

diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
index 1b23e541531147f264f38e73991a7ee1ca82b433..2d1925018eb47bcc1bd5da45a3d3fec8cac0446e 100644 (file)
--- a/libavcodec/apedec.c
+++ b/libavcodec/apedec.c
@@ -586,6 +586,11 @@ static inline int ape_decode_value_3990(APEContext *ctx, APERice *rice)
     return ((x >> 1) ^ ((x & 1) - 1)) + 1;
 }
 
+static int get_k(int ksum)
+{
+    return av_log2(ksum) + !!ksum;
+}
+
 static void decode_array_0000(APEContext *ctx, GetBitContext *gb,
                               int32_t *out, APERice *rice, int blockstodecode)
 {
@@ -597,25 +602,34 @@ static void decode_array_0000(APEContext *ctx, GetBitContext *gb,
         out[i] = get_rice_ook(&ctx->gb, 10);
         rice->ksum += out[i];
     }
-    rice->k = av_log2(rice->ksum / 10) + 1;
+
+    if (blockstodecode <= 5)
+        goto end;
+
+    rice->k = get_k(rice->ksum / 10);
     if (rice->k >= 24)
         return;
     for (; i < FFMIN(blockstodecode, 64); i++) {
         out[i] = get_rice_ook(&ctx->gb, rice->k);
         rice->ksum += out[i];
-        rice->k = av_log2(rice->ksum / ((i + 1) * 2)) + 1;
+        rice->k = get_k(rice->ksum / ((i + 1) * 2));
         if (rice->k >= 24)
             return;
     }
+
+    if (blockstodecode <= 64)
+        goto end;
+
+    rice->k = get_k(rice->ksum >> 7);
     ksummax = 1 << rice->k + 7;
     ksummin = rice->k ? (1 << rice->k + 6) : 0;
     for (; i < blockstodecode; i++) {
         if (get_bits_left(&ctx->gb) < 1) {
             ctx->error = 1;
-            return ;
+            return;
         }
         out[i] = get_rice_ook(&ctx->gb, rice->k);
-        rice->ksum += out[i] - out[i - 64];
+        rice->ksum += out[i] - (unsigned)out[i - 64];
         while (rice->ksum < ksummin) {
             rice->k--;
             ksummin = rice->k ? ksummin >> 1 : 0;
@@ -630,6 +644,7 @@ static void decode_array_0000(APEContext *ctx, GetBitContext *gb,
         }
     }
 
+end:
     for (i = 0; i < blockstodecode; i++)
         out[i] = ((out[i] >> 1) ^ ((out[i] & 1) - 1)) + 1;
 }
@@ -1208,14 +1223,14 @@ static void predictor_decode_mono_3950(APEContext *ctx, int count)
         A = *decoded0;
 
         p->buf[YDELAYA] = currentA;
-        p->buf[YDELAYA - 1] = p->buf[YDELAYA] - p->buf[YDELAYA - 1];
+        p->buf[YDELAYA - 1] = p->buf[YDELAYA] - (unsigned)p->buf[YDELAYA - 1];
 
         predictionA = p->buf[YDELAYA    ] * p->coeffsA[0][0] +
                       p->buf[YDELAYA - 1] * p->coeffsA[0][1] +
                       p->buf[YDELAYA - 2] * p->coeffsA[0][2] +
                       p->buf[YDELAYA - 3] * p->coeffsA[0][3];
 
-        currentA = A + (predictionA >> 10);
+        currentA = A + (unsigned)(predictionA >> 10);
 
         p->buf[YADAPTCOEFFSA]     = APESIGN(p->buf[YDELAYA    ]);
         p->buf[YADAPTCOEFFSA - 1] = APESIGN(p->buf[YDELAYA - 1]);
@@ -1555,7 +1570,7 @@ static int ape_decode_frame(AVCodecContext *avctx, void *data,
         for (ch = 0; ch < s->channels; ch++) {
             sample24 = (int32_t *)frame->data[ch];
             for (i = 0; i < blockstodecode; i++)
-                *sample24++ = s->decoded[ch][i] << 8;
+                *sample24++ = s->decoded[ch][i] * 256;
         }
         break;
     }