+static int hevc_decode_extradata(HEVCContext *s)
+{
+ AVCodecContext *avctx = s->avctx;
+ GetByteContext gb;
+ int ret, i;
+
+ bytestream2_init(&gb, avctx->extradata, avctx->extradata_size);
+
+ if (avctx->extradata_size > 3 &&
+ (avctx->extradata[0] || avctx->extradata[1] ||
+ avctx->extradata[2] > 1)) {
+ /* It seems the extradata is encoded as hvcC format.
+ * Temporarily, we support configurationVersion==0 until 14496-15 3rd
+ * is finalized. When finalized, configurationVersion will be 1 and we
+ * can recognize hvcC by checking if avctx->extradata[0]==1 or not. */
+ int i, j, num_arrays, nal_len_size;
+
+ s->is_nalff = 1;
+
+ bytestream2_skip(&gb, 21);
+ nal_len_size = (bytestream2_get_byte(&gb) & 3) + 1;
+ num_arrays = bytestream2_get_byte(&gb);
+
+ /* nal units in the hvcC always have length coded with 2 bytes,
+ * so put a fake nal_length_size = 2 while parsing them */
+ s->nal_length_size = 2;
+
+ /* Decode nal units from hvcC. */
+ for (i = 0; i < num_arrays; i++) {
+ int type = bytestream2_get_byte(&gb) & 0x3f;
+ int cnt = bytestream2_get_be16(&gb);
+
+ for (j = 0; j < cnt; j++) {
+ // +2 for the nal size field
+ int nalsize = bytestream2_peek_be16(&gb) + 2;
+ if (bytestream2_get_bytes_left(&gb) < nalsize) {
+ av_log(s->avctx, AV_LOG_ERROR,
+ "Invalid NAL unit size in extradata.\n");
+ return AVERROR_INVALIDDATA;
+ }
+
+ ret = decode_nal_units(s, gb.buffer, nalsize);
+ if (ret < 0) {
+ av_log(avctx, AV_LOG_ERROR,
+ "Decoding nal unit %d %d from hvcC failed\n",
+ type, i);
+ return ret;
+ }
+ bytestream2_skip(&gb, nalsize);
+ }
+ }
+
+ /* Now store right nal length size, that will be used to parse
+ * all other nals */
+ s->nal_length_size = nal_len_size;
+ } else {
+ s->is_nalff = 0;
+ ret = decode_nal_units(s, avctx->extradata, avctx->extradata_size);
+ if (ret < 0)
+ return ret;
+ }
+
+ /* export stream parameters from the first SPS */
+ for (i = 0; i < FF_ARRAY_ELEMS(s->ps.sps_list); i++) {
+ if (s->ps.sps_list[i]) {
+ const HEVCSPS *sps = (const HEVCSPS*)s->ps.sps_list[i]->data;
+ export_stream_params(s->avctx, &s->ps, sps);
+ break;
+ }
+ }
+
+ return 0;
+}
+