libavcodec/hevc_mp4toannexb_bsf.c: Optional argument "private_spspps_buf" to avoid extradata modification.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/hevc_mp4toannexb_bsf.c

@@ -35,9 +35,21 @@ typedef struct HEVCBSFContext {
     int      extradata_parsed;
 
     int logged_nonmp4_warning;
+
+    /* When private_spspps is zero then spspps_buf points to global extradata
+       and bsf does replace a global extradata to own-allocated version (default
+       behaviour).
+       When private_spspps is non-zero the bsf uses a private version of spspps buf.
+       This mode necessary when bsf uses in decoder, else bsf has issues after
+       decoder re-initialization. Use the "private_spspps_buf" argument to
+       activate this mode.
+     */
+    int      private_spspps;
+    uint8_t *spspps_buf;
+    uint32_t spspps_size;
 } HEVCBSFContext;
 
-static int hevc_extradata_to_annexb(AVCodecContext *avctx)
+static int hevc_extradata_to_annexb(HEVCBSFContext* ctx, AVCodecContext *avctx)
 {
     GetByteContext gb;
     int length_size, num_arrays, i, j;
@@ -82,9 +94,13 @@ static int hevc_extradata_to_annexb(AVCodecContext *avctx)
         }
     }
 
-    av_freep(&avctx->extradata);
-    avctx->extradata      = new_extradata;
-    avctx->extradata_size = new_extradata_size;
+    if (!ctx->private_spspps) {
+        av_freep(&avctx->extradata);
+        avctx->extradata      = new_extradata;
+        avctx->extradata_size = new_extradata_size;
+    }
+    ctx->spspps_buf  = new_extradata;
+    ctx->spspps_size = new_extradata_size;
 
     if (!new_extradata_size)
         av_log(avctx, AV_LOG_WARNING, "No parameter sets in the extradata\n");
@@ -122,8 +138,10 @@ static int hevc_mp4toannexb_filter(AVBitStreamFilterContext *bsfc,
             *poutbuf_size = buf_size;
             return 0;
         }
+        if (args && strstr(args, "private_spspps_buf"))
+            ctx->private_spspps = 1;
 
-        ret = hevc_extradata_to_annexb(avctx);
+        ret = hevc_extradata_to_annexb(ctx, avctx);
         if (ret < 0)
             return ret;
         ctx->length_size      = ret;
@@ -148,7 +166,7 @@ static int hevc_mp4toannexb_filter(AVBitStreamFilterContext *bsfc,
         /* prepend extradata to IRAP frames */
         is_irap       = nalu_type >= 16 && nalu_type <= 23;
         add_extradata = is_irap && !got_irap;
-        extra_size    = add_extradata * avctx->extradata_size;
+        extra_size    = add_extradata * ctx->spspps_size;
         got_irap     |= is_irap;
 
         if (SIZE_MAX - out_size < 4             ||
@@ -163,7 +181,7 @@ static int hevc_mp4toannexb_filter(AVBitStreamFilterContext *bsfc,
             goto fail;
 
         if (add_extradata)
-            memcpy(out + out_size, avctx->extradata, extra_size);
+            memcpy(out + out_size, ctx->spspps_buf, extra_size);
         AV_WB32(out + out_size + extra_size, 1);
         bytestream2_get_buffer(&gb, out + out_size + 4 + extra_size, nalu_size);
         out_size += 4 + nalu_size + extra_size;
@@ -179,8 +197,16 @@ fail:
     return ret;
 }
 
+static void hevc_mp4toannexb_close(AVBitStreamFilterContext *bsfc)
+{
+    HEVCBSFContext *ctx = bsfc->priv_data;
+    if (ctx->private_spspps)
+        av_freep(&ctx->spspps_buf);
+}
+
 AVBitStreamFilter ff_hevc_mp4toannexb_bsf = {
     "hevc_mp4toannexb",
     sizeof(HEVCBSFContext),
     hevc_mp4toannexb_filter,
+    hevc_mp4toannexb_close,
 };