lavc: set AVCodecContext.hwaccel in ff_get_format()

This way each decoder does not have to do the same thing manually.

libavcodec/h263dec.c

@@ -108,7 +108,6 @@ av_cold int ff_h263_decode_init(AVCodecContext *avctx)
         return AVERROR(ENOSYS);
     }
     s->codec_id    = avctx->codec->id;
-    avctx->hwaccel = ff_find_hwaccel(avctx);
 
     /* for h263, we allocate the images after having read the header */
     if (avctx->codec->id != AV_CODEC_ID_H263 &&

libavcodec/h264_slice.c

@@ -1078,8 +1078,6 @@ static int h264_slice_header_init(H264Context *h, int reinit)
                   h->sps.num_units_in_tick, den, 1 << 30);
     }
 
-    h->avctx->hwaccel = ff_find_hwaccel(h->avctx);
-
     if (reinit)
         ff_h264_free_tables(h, 0);
     h->first_field           = 0;

libavcodec/internal.h

@@ -102,15 +102,6 @@ struct AVCodecDefault {
     const uint8_t *value;
 };
 
-/**
- * Return the hardware accelerated codec for codec codec_id and
- * pixel format pix_fmt.
- *
- * @param avctx The codec context containing the codec_id and pixel format.
- * @return the hardware accelerated codec, or NULL if none was found.
- */
-AVHWAccel *ff_find_hwaccel(AVCodecContext *avctx);
-
 /**
  * Return the index into tab at which {a,b} match elements {[0],[1]} of tab.
  * If there is no such matching pair then size is returned.

libavcodec/mpeg12dec.c

@@ -1295,7 +1295,6 @@ static int mpeg_decode_postinit(AVCodecContext *avctx)
         } // MPEG-2
 
         avctx->pix_fmt = mpeg_get_pixelformat(avctx);
-        avctx->hwaccel = ff_find_hwaccel(avctx);
         // until then pix_fmt may be changed right after codec init
 #if FF_API_XVMC
         if ((avctx->pix_fmt == AV_PIX_FMT_XVMC_MPEG2_IDCT ||
@@ -2126,7 +2125,6 @@ static int vcr2_init_sequence(AVCodecContext *avctx)
     s->low_delay        = 1;
 
     avctx->pix_fmt = mpeg_get_pixelformat(avctx);
-    avctx->hwaccel = ff_find_hwaccel(avctx);
 
 #if FF_API_XVMC
     if ((avctx->pix_fmt == AV_PIX_FMT_XVMC_MPEG2_IDCT || avctx->hwaccel) &&

libavcodec/utils.c

@@ -864,9 +864,41 @@ enum AVPixelFormat avcodec_default_get_format(struct AVCodecContext *s, const en
     return fmt[0];
 }
 
+static AVHWAccel *find_hwaccel(enum AVCodecID codec_id,
+                               enum AVPixelFormat pix_fmt)
+{
+    AVHWAccel *hwaccel = NULL;
+
+    while ((hwaccel = av_hwaccel_next(hwaccel)))
+        if (hwaccel->id == codec_id
+            && hwaccel->pix_fmt == pix_fmt)
+            return hwaccel;
+    return NULL;
+}
+
+
 int ff_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt)
 {
-    return avctx->get_format(avctx, fmt);
+    const AVPixFmtDescriptor *desc;
+    enum AVPixelFormat ret = avctx->get_format(avctx, fmt);
+
+    desc = av_pix_fmt_desc_get(ret);
+    if (!desc)
+        return AV_PIX_FMT_NONE;
+
+    if (desc->flags & AV_PIX_FMT_FLAG_HWACCEL) {
+        avctx->hwaccel = find_hwaccel(avctx->codec_id, ret);
+        if (!avctx->hwaccel) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Could not find an AVHWAccel for the pixel format: %s",
+                   desc->name);
+            return AV_PIX_FMT_NONE;
+        }
+    } else {
+        avctx->hwaccel = NULL;
+    }
+
+    return ret;
 }
 
 #if FF_API_AVFRAME_LAVC
@@ -2207,20 +2239,6 @@ AVHWAccel *av_hwaccel_next(AVHWAccel *hwaccel)
     return hwaccel ? hwaccel->next : first_hwaccel;
 }
 
-AVHWAccel *ff_find_hwaccel(AVCodecContext *avctx)
-{
-    enum AVCodecID codec_id = avctx->codec->id;
-    enum AVPixelFormat pix_fmt = avctx->pix_fmt;
-
-    AVHWAccel *hwaccel = NULL;
-
-    while ((hwaccel = av_hwaccel_next(hwaccel)))
-        if (hwaccel->id == codec_id
-            && hwaccel->pix_fmt == pix_fmt)
-            return hwaccel;
-    return NULL;
-}
-
 int av_lockmgr_register(int (*cb)(void **mutex, enum AVLockOp op))
 {
     if (lockmgr_cb) {

libavcodec/vc1dec.c

@@ -5598,7 +5598,6 @@ static av_cold int vc1_decode_init(AVCodecContext *avctx)
         avctx->pix_fmt = ff_get_format(avctx, avctx->codec->pix_fmts);
     else
         avctx->pix_fmt = AV_PIX_FMT_GRAY8;
-    avctx->hwaccel = ff_find_hwaccel(avctx);
     v->s.avctx = avctx;
 
     if (ff_vc1_init_common(v) < 0)