vulkan_decode: adjust number of async contexts created

This caps the number of contexts we create based on thread count.
This saves VRAM and filters out cases where more async is of lesser
benefit.

1 files changed, 8 insertions, 2 deletions

diff --git a/libavcodec/vulkan_decode.c b/libavcodec/vulkan_decode.c
index 7f638d6fc6..cd77e10e12 100644
--- a/libavcodec/vulkan_decode.c
+++ b/libavcodec/vulkan_decode.c
@@ -1122,6 +1122,7 @@ int ff_vk_decode_init(AVCodecContext *avctx)
     FFVulkanDecodeShared *ctx;
     FFVulkanContext *s;
     FFVulkanFunctions *vk;
+    int async_depth;
     const VkVideoProfileInfoKHR *profile;
     const FFVulkanDecodeDescriptor *vk_desc;
     const VkPhysicalDeviceDriverProperties *driver_props;
@@ -1191,9 +1192,14 @@ int ff_vk_decode_init(AVCodecContext *avctx)
     /* Create decode exec context for this specific main thread.
      * 2 async contexts per thread was experimentally determined to be optimal
      * for a majority of streams. */
+    async_depth = 2*ctx->qf->num;
+    /* We don't need more than 2 per thread context */
+    async_depth = FFMIN(async_depth, 2*avctx->thread_count);
+    /* Make sure there are enough async contexts for each thread */
+    async_depth = FFMAX(async_depth, avctx->thread_count);
+
     err = ff_vk_exec_pool_init(s, ctx->qf, &ctx->exec_pool,
-                               FFMAX(2*ctx->qf->num, avctx->thread_count),
-                               0, 0, 0, profile);
+                               async_depth, 0, 0, 0, profile);
     if (err < 0)
         goto fail;