libopenh264: Add support for decoding of b-frames

The current git master version of libopenh264 supports decoding of
b-frames.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavcodec/libopenh264dec.c

@@ -96,7 +96,18 @@ static int svc_decode_frame(AVCodecContext *avctx, void *data,
     AVFrame *avframe = data;
     DECODING_STATE state;
 
-    state = (*s->decoder)->DecodeFrame2(s->decoder, avpkt->data, avpkt->size, ptrs, &info);
+    if (!avpkt->data) {
+#if OPENH264_VER_AT_LEAST(1, 9)
+        int end_of_stream = 1;
+        (*s->decoder)->SetOption(s->decoder, DECODER_OPTION_END_OF_STREAM, &end_of_stream);
+        state = (*s->decoder)->FlushFrame(s->decoder, ptrs, &info);
+#else
+        return 0;
+#endif
+    } else {
+        info.uiInBsTimeStamp = avpkt->pts;
+        state = (*s->decoder)->DecodeFrame2(s->decoder, avpkt->data, avpkt->size, ptrs, &info);
+    }
     if (state != dsErrorFree) {
         av_log(avctx, AV_LOG_ERROR, "DecodeFrame2 failed\n");
         return AVERROR_UNKNOWN;
@@ -118,8 +129,8 @@ static int svc_decode_frame(AVCodecContext *avctx, void *data,
     linesize[1] = linesize[2] = info.UsrData.sSystemBuffer.iStride[1];
     av_image_copy(avframe->data, avframe->linesize, (const uint8_t **) ptrs, linesize, avctx->pix_fmt, avctx->width, avctx->height);
 
-    avframe->pts     = avpkt->pts;
-    avframe->pkt_dts = avpkt->dts;
+    avframe->pts     = info.uiOutYuvTimeStamp;
+    avframe->pkt_dts = AV_NOPTS_VALUE;
 #if FF_API_PKT_PTS
 FF_DISABLE_DEPRECATION_WARNINGS
     avframe->pkt_pts = avpkt->pts;
@@ -139,8 +150,6 @@ AVCodec ff_libopenh264_decoder = {
     .init           = svc_decode_init,
     .decode         = svc_decode_frame,
     .close          = svc_decode_close,
-    // The decoder doesn't currently support B-frames, and the decoder's API
-    // doesn't support reordering/delay, but the BSF could incur delay.
     .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_DR1,
     .caps_internal  = FF_CODEC_CAP_SETS_PKT_DTS | FF_CODEC_CAP_INIT_THREADSAFE |
                       FF_CODEC_CAP_INIT_CLEANUP,