lavc: Add wrapped_avframe decoder

Intended for use with hardware frames for which rawvideo is not
sufficient.  Requires the trusted packet flag to be set - decoding
fails if not to avoid security issues (the wrapped AVFrame can
contain pointers to arbitrary data).

libavcodec/Makefile

@@ -653,6 +653,7 @@ OBJS-$(CONFIG_WMV2_DECODER)            += wmv2dec.o wmv2.o wmv2data.o \
 OBJS-$(CONFIG_WMV2_ENCODER)            += wmv2enc.o wmv2.o wmv2data.o \
                                           msmpeg4.o msmpeg4enc.o msmpeg4data.o
 OBJS-$(CONFIG_WNV1_DECODER)            += wnv1.o
+OBJS-$(CONFIG_WRAPPED_AVFRAME_DECODER) += wrapped_avframe.o
 OBJS-$(CONFIG_WRAPPED_AVFRAME_ENCODER) += wrapped_avframe.o
 OBJS-$(CONFIG_WS_SND1_DECODER)         += ws-snd1.o
 OBJS-$(CONFIG_XAN_DPCM_DECODER)        += dpcm.o

libavcodec/allcodecs.c

@@ -377,7 +377,7 @@ static void register_all(void)
     REGISTER_DECODER(VQA,               vqa);
     REGISTER_DECODER(BITPACKED,         bitpacked);
     REGISTER_DECODER(WEBP,              webp);
-    REGISTER_ENCODER(WRAPPED_AVFRAME,   wrapped_avframe);
+    REGISTER_ENCDEC (WRAPPED_AVFRAME,   wrapped_avframe);
     REGISTER_ENCDEC (WMV1,              wmv1);
     REGISTER_ENCDEC (WMV2,              wmv2);
     REGISTER_DECODER(WMV3,              wmv3);

libavcodec/version.h

@@ -29,7 +29,7 @@
 
 #define LIBAVCODEC_VERSION_MAJOR  57
 #define LIBAVCODEC_VERSION_MINOR 106
-#define LIBAVCODEC_VERSION_MICRO 100
+#define LIBAVCODEC_VERSION_MICRO 101
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \

libavcodec/wrapped_avframe.c

@@ -75,6 +75,33 @@ static int wrapped_avframe_encode(AVCodecContext *avctx, AVPacket *pkt,
     return 0;
 }
 
+static int wrapped_avframe_decode(AVCodecContext *avctx, void *data,
+                                  int *got_frame, AVPacket *pkt)
+{
+    AVFrame *in, *out;
+    int err;
+
+    if (!(pkt->flags & AV_PKT_FLAG_TRUSTED)) {
+        // This decoder is not usable with untrusted input.
+        return AVERROR(EPERM);
+    }
+
+    if (pkt->size < sizeof(AVFrame))
+        return AVERROR(EINVAL);
+
+    in  = (AVFrame*)pkt->data;
+    out = data;
+
+    err = ff_decode_frame_props(avctx, out);
+    if (err < 0)
+        return err;
+
+    av_frame_move_ref(out, in);
+
+    *got_frame = 1;
+    return 0;
+}
+
 AVCodec ff_wrapped_avframe_encoder = {
     .name           = "wrapped_avframe",
     .long_name      = NULL_IF_CONFIG_SMALL("AVFrame to AVPacket passthrough"),
@@ -83,3 +110,12 @@ AVCodec ff_wrapped_avframe_encoder = {
     .encode2        = wrapped_avframe_encode,
     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
 };
+
+AVCodec ff_wrapped_avframe_decoder = {
+    .name           = "wrapped_avframe",
+    .long_name      = NULL_IF_CONFIG_SMALL("AVPacket to AVFrame passthrough"),
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_WRAPPED_AVFRAME,
+    .decode         = wrapped_avframe_decode,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
+};