lavu/hwcontext_qsv: update AVQSVFramesContext to support dynamic frame pool

Add AVQSVFramesContext.info and update the description.
Signed-off-by: Haihao Xiang <haihao.xiang@intel.com>

doc/APIchanges

@@ -2,6 +2,9 @@ The last version increases of all libraries were on 2024-03-07
 
 API changes, most recent first:
 
+2024-05-xx - xxxxxxxxxx - lavu 59.19.100 - hwcontext_qsv.h
+  Add AVQSVFramesContext.info
+
 2024-05-10 - xxxxxxxxx - lavu 59.18.100 - cpu.h
   Add AV_CPU_FLAG_RV_ZVBB.
 

libavutil/hwcontext_qsv.c

@@ -627,7 +627,7 @@ static mfxStatus frame_alloc(mfxHDL pthis, mfxFrameAllocRequest *req,
     QSVFramesContext       *s = ctx->hwctx;
     AVQSVFramesContext *hwctx = &s->p;
     mfxFrameInfo *i  = &req->Info;
-    mfxFrameInfo *i1 = &hwctx->surfaces[0].Info;
+    mfxFrameInfo *i1 = hwctx->nb_surfaces ? &hwctx->surfaces[0].Info : hwctx->info;
 
     if (!(req->Type & MFX_MEMTYPE_VIDEO_MEMORY_PROCESSOR_TARGET) ||
         !(req->Type & (MFX_MEMTYPE_FROM_VPPIN | MFX_MEMTYPE_FROM_VPPOUT)) ||
@@ -1207,7 +1207,7 @@ static int qsv_init_internal_session(AVHWFramesContext *ctx,
                               MFX_IOPATTERN_OUT_SYSTEM_MEMORY;
     par.AsyncDepth = 1;
 
-    par.vpp.In = frames_hwctx->surfaces[0].Info;
+    par.vpp.In = frames_hwctx->nb_surfaces ? frames_hwctx->surfaces[0].Info : *frames_hwctx->info;
 
     /* Apparently VPP requires the frame rate to be set to some value, otherwise
      * init will fail (probably for the framerate conversion filter). Since we

libavutil/hwcontext_qsv.h

@@ -25,8 +25,8 @@
  * @file
  * An API-specific header for AV_HWDEVICE_TYPE_QSV.
  *
- * This API does not support dynamic frame pools. AVHWFramesContext.pool must
- * contain AVBufferRefs whose data pointer points to an mfxFrameSurface1 struct.
+ * AVHWFramesContext.pool must contain AVBufferRefs whose data pointer points
+ * to a mfxFrameSurface1 struct.
  */
 
 /**
@@ -51,13 +51,36 @@ typedef struct AVQSVDeviceContext {
  * This struct is allocated as AVHWFramesContext.hwctx
  */
 typedef struct AVQSVFramesContext {
+    /**
+     * A pointer to a mfxFrameSurface1 struct
+     *
+     * It is available when nb_surfaces is non-zero.
+     */
     mfxFrameSurface1 *surfaces;
+
+    /**
+     * Number of frames in the pool
+     *
+     * It is 0 for dynamic frame pools or AVHWFramesContext.initial_pool_size
+     * for fixed frame pools.
+     *
+     * Note only oneVPL GPU runtime 2.9+ can support dynamic frame pools
+     * on d3d11va or vaapi
+     */
     int            nb_surfaces;
 
     /**
      * A combination of MFX_MEMTYPE_* describing the frame pool.
      */
     int frame_type;
+
+    /**
+     * A pointer to a mfxFrameInfo struct
+     *
+     * It is available when nb_surfaces is 0, all buffers allocated from the
+     * pool have the same mfxFrameInfo.
+     */
+    mfxFrameInfo *info;
 } AVQSVFramesContext;
 
 #endif /* AVUTIL_HWCONTEXT_QSV_H */

libavutil/version.h

@@ -79,7 +79,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  59
-#define LIBAVUTIL_VERSION_MINOR  18
+#define LIBAVUTIL_VERSION_MINOR  19
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \