diff --git a/src/intel/vulkan_hasvk/anv_video.c b/src/intel/vulkan_hasvk/anv_video.c
index 42b7464..9fe93cd 100644
--- a/src/intel/vulkan_hasvk/anv_video.c
+++ b/src/intel/vulkan_hasvk/anv_video.c
@@ -237,11 +237,12 @@ anv_GetPhysicalDeviceVideoCapabilitiesKHR(VkPhysicalDevice physicalDevice,
       if (ir_caps) {
          /* Each macroblock's intra/inter decision is made on its own when the
           * PAK objects are emitted, so the picture can be split along any of
-          * these axes.  Per-picture-partition mode is not offered: it wants the
-          * refreshed slice coded as an I slice, header included, rather than as
-          * intra macroblocks inside a P slice.
+          * these axes.  Per-picture-partition mode needs nothing extra: the
+          * refreshed partition is a slice the client marks as an I slice, and
+          * slices are already coded according to their own slice_type.
           */
          ir_caps->intraRefreshModes =
+            VK_VIDEO_ENCODE_INTRA_REFRESH_MODE_PER_PICTURE_PARTITION_BIT_KHR |
             VK_VIDEO_ENCODE_INTRA_REFRESH_MODE_BLOCK_BASED_BIT_KHR |
             VK_VIDEO_ENCODE_INTRA_REFRESH_MODE_BLOCK_ROW_BASED_BIT_KHR |
             VK_VIDEO_ENCODE_INTRA_REFRESH_MODE_BLOCK_COLUMN_BASED_BIT_KHR;
diff --git a/src/intel/vulkan_hasvk/genX_cmd_video.c b/src/intel/vulkan_hasvk/genX_cmd_video.c
index 278ff00..a6e0db3 100644
--- a/src/intel/vulkan_hasvk/genX_cmd_video.c
+++ b/src/intel/vulkan_hasvk/genX_cmd_video.c
@@ -1178,11 +1178,17 @@ anv_h264_encode_video(struct anv_cmd_buffer *cmd_buffer,
       intra_refresh_ptr = &intra_refresh;
    }
 
-   /* Emit each slice. Slice s covers the macroblock range
-    * [first_mb_in_slice[s], first_mb_in_slice[s+1]); the last slice runs to the
-    * end of the frame. Each NALU slice entry carries its own QP and slice
-    * header. The MFC appends slices in the destination buffer automatically. */
+   /* Emit each slice.  Partitioning the picture is the implementation's job:
+    * first_mb_in_slice is something the driver derives and writes into the
+    * emitted header, not something the client hands down -- clients leave it
+    * at zero for every entry.  Divide the macroblock rows evenly across the
+    * NALU slice entries, which also keeps every slice row-aligned, as
+    * VK_VIDEO_ENCODE_H264_CAPABILITY_ROW_UNALIGNED_SLICE_BIT_KHR is not
+    * advertised.  Each entry carries its own QP and slice header; the MFC
+    * appends slices in the destination buffer automatically. */
    uint32_t slice_count = h264_pic_info->naluSliceEntryCount;
+   if (slice_count > height_in_mbs)
+      return VK_ERROR_INITIALIZATION_FAILED;
    for (uint32_t s = 0; s < slice_count; s++) {
       const VkVideoEncodeH264NaluSliceInfoKHR *entry =
          &h264_pic_info->pNaluSliceEntries[s];
@@ -1192,27 +1198,9 @@ anv_h264_encode_video(struct anv_cmd_buffer *cmd_buffer,
       if (entry->constantQp < 0 || entry->constantQp > 51)
          return VK_ERROR_INITIALIZATION_FAILED;
 
-      uint32_t slice_start_mb = sh->first_mb_in_slice;
-      uint32_t slice_end_mb = total_mbs;
-      if (s + 1 < slice_count) {
-         const StdVideoEncodeH264SliceHeader *next_sh =
-            h264_pic_info->pNaluSliceEntries[s + 1].pStdSliceHeader;
-         if (!next_sh)
-            return VK_ERROR_INITIALIZATION_FAILED;
-         slice_end_mb = next_sh->first_mb_in_slice;
-      }
-
-      /* H.264 requires the first slice of a picture to start at macroblock 0
-       * (7.4.3: first_mb_in_slice of the first slice is 0). ffmpeg's h264_vulkan
-       * encoder violates this — it passes first_mb_in_slice=1 for the sole slice.
-       * Trusting that value skips MB 0, so the MFC only receives total_mbs-1 PAK
-       * objects for a frame it knows has total_mbs macroblocks; it then waits
-       * forever for the missing MB and the VCS ring hangs ("stopped heartbeat",
-       * no page fault, parked on MFC_AVC_PAK_OBJECT). Force the first slice to
-       * start at MB 0 so the frame is fully covered and the emitted slice header
-       * stays consistent with the coded data. */
-      if (s == 0)
-         slice_start_mb = 0;
+      uint32_t slice_start_mb = s * height_in_mbs / slice_count * width_in_mbs;
+      uint32_t slice_end_mb =
+         (s + 1) * height_in_mbs / slice_count * width_in_mbs;
 
       if (getenv("HASVK_ENC_LOG"))
          mesa_logi("ENC slice[%u] first_mb_in_slice=%u -> start=%u end=%u total_mbs=%u",