Use signed int type for av1_lookahead_init params

Callers of av1_lookahead_init pass signed int variables as those
parameters, and av1_lookahead_init passes those parameters to a function
that receives signed int parameters.

Also change av1_lookahead_depth to return signed int.

A port of the libaom CL
https://aomedia-review.googlesource.com/c/aom/+/201201.

av1/encoder/lookahead.c

diff --git a/av1/encoder/lookahead.c b/av1/encoder/lookahead.c
index 476ea8e..78fcf92 100644
--- a/av1/encoder/lookahead.c
+++ b/av1/encoder/lookahead.c
@@ -43,15 +43,16 @@
   }
 }
 
-struct lookahead_ctx *av1_lookahead_init(
-    unsigned int width, unsigned int height, unsigned int subsampling_x,
-    unsigned int subsampling_y, unsigned int depth, const int border_in_pixels,
-    int byte_alignment, int num_lap_buffers,
+struct lookahead_ctx *av1_lookahead_init(int width, int height,
+                                         int subsampling_x, int subsampling_y,
+                                         int depth, const int border_in_pixels,
+                                         int byte_alignment,
+                                         int num_lap_buffers,
 #if CONFIG_BRU  // BRU need extra look ahead buffer to store the src of
                 // reference frame (org pixels)
-    int num_extra_buffers,
+                                         int num_extra_buffers,
 #endif  // CONFIG_BRU
-    bool alloc_pyramid) {
+                                         bool alloc_pyramid) {
   struct lookahead_ctx *ctx = NULL;
   int lag_in_frames = AOMMAX(1, depth);
 
@@ -67,7 +68,6 @@
   // Allocate the lookahead structures
   ctx = calloc(1, sizeof(*ctx));
   if (ctx) {
-    unsigned int i;
     ctx->max_sz = depth;
 #if CONFIG_BRU
     ctx->read_ctxs[ENCODE_STAGE].pop_sz =
@@ -84,7 +84,7 @@
     }
     ctx->buf = calloc(depth, sizeof(*ctx->buf));
     if (!ctx->buf) goto fail;
-    for (i = 0; i < depth; i++) {
+    for (int i = 0; i < depth; i++) {
       aom_free_frame_buffer(&ctx->buf[i].img);
       if (aom_realloc_frame_buffer(&ctx->buf[i].img, width, height,
                                    subsampling_x, subsampling_y,
@@ -284,8 +284,7 @@
   return buf;
 }
 
-unsigned int av1_lookahead_depth(struct lookahead_ctx *ctx,
-                                 COMPRESSOR_STAGE stage) {
+int av1_lookahead_depth(struct lookahead_ctx *ctx, COMPRESSOR_STAGE stage) {
   struct read_ctx *read_ctx = NULL;
   assert(ctx != NULL);
 

av1/encoder/lookahead.h

diff --git a/av1/encoder/lookahead.h b/av1/encoder/lookahead.h
index 45ff485..f12f888 100644
--- a/av1/encoder/lookahead.h
+++ b/av1/encoder/lookahead.h
@@ -68,14 +68,15 @@
  * The lookahead stage is a queue of frame buffers on which some analysis
  * may be done when buffers are enqueued.
  */
-struct lookahead_ctx *av1_lookahead_init(
-    unsigned int width, unsigned int height, unsigned int subsampling_x,
-    unsigned int subsampling_y, unsigned int depth, const int border_in_pixels,
-    int byte_alignment, int num_lap_buffers,
+struct lookahead_ctx *av1_lookahead_init(int width, int height,
+                                         int subsampling_x, int subsampling_y,
+                                         int depth, const int border_in_pixels,
+                                         int byte_alignment,
+                                         int num_lap_buffers,
 #if CONFIG_BRU
-    int num_extra_buffers,
+                                         int num_extra_buffers,
 #endif  // CONFIG_BRU
-    bool alloc_pyramid);
+                                         bool alloc_pyramid);
 
 /**\brief Destroys the lookahead stage
  */
@@ -152,8 +153,7 @@
 
 /**\brief Get the number of frames currently in the lookahead queue
  */
-unsigned int av1_lookahead_depth(struct lookahead_ctx *ctx,
-                                 COMPRESSOR_STAGE stage);
+int av1_lookahead_depth(struct lookahead_ctx *ctx, COMPRESSOR_STAGE stage);
 
 /**\brief Get pop_sz value
  */

av1/encoder/pass2_strategy.c

diff --git a/av1/encoder/pass2_strategy.c b/av1/encoder/pass2_strategy.c
index 389c2cf..1029f2f 100644
--- a/av1/encoder/pass2_strategy.c
+++ b/av1/encoder/pass2_strategy.c
@@ -1413,7 +1413,7 @@
 
 static void correct_frames_to_key(AV1_COMP *cpi) {
   int lookahead_size =
-      (int)av1_lookahead_depth(cpi->lookahead, cpi->compressor_stage);
+      av1_lookahead_depth(cpi->lookahead, cpi->compressor_stage);
   if (lookahead_size <
       av1_lookahead_pop_sz(cpi->lookahead, cpi->compressor_stage)) {
     cpi->rc.frames_to_key = AOMMIN(cpi->rc.frames_to_key, lookahead_size);
@@ -1425,7 +1425,7 @@
 
 static int is_last_subgop(AV1_COMP *cpi) {
   const int lookahead_size =
-      (int)av1_lookahead_depth(cpi->lookahead, cpi->compressor_stage);
+      av1_lookahead_depth(cpi->lookahead, cpi->compressor_stage);
   // Check if last subgop in the clip.
   const int is_last_sub = (cpi->oxcf.gf_cfg.lag_in_frames > lookahead_size) &&
                           (lookahead_size == cpi->rc.frames_to_key);