avauddec: address regression with WMA files ..

By outputting lead-in samples that FFmpeg now would like us to ignore,
and discarding trailing samples that it would now like us to output.

See https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1474

Fixes: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1348
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3117>

diff --git a/subprojects/gst-libav/ext/libav/gstavauddec.c b/subprojects/gst-libav/ext/libav/gstavauddec.c
index 68ab1dc..d12f9b2 100644 (file)
--- a/subprojects/gst-libav/ext/libav/gstavauddec.c
+++ b/subprojects/gst-libav/ext/libav/gstavauddec.c
@@ -221,6 +221,14 @@ gst_ffmpegauddec_start (GstAudioDecoder * decoder)
     return FALSE;
   }
   ffmpegdec->context->opaque = ffmpegdec;
+
+  /* FIXME: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1474 */
+  if ((oclass->in_plugin->capabilities & AV_CODEC_CAP_DELAY) != 0
+      && (oclass->in_plugin->id == AV_CODEC_ID_WMAV1
+          || oclass->in_plugin->id == AV_CODEC_ID_WMAV2)) {
+    ffmpegdec->context->flags2 |= AV_CODEC_FLAG2_SKIP_MANUAL;
+  }
+
   GST_OBJECT_UNLOCK (ffmpegdec);
 
   return TRUE;
@@ -608,11 +616,14 @@ gst_ffmpegauddec_drain (GstFFMpegAudDec * ffmpegdec, gboolean force)
   if (avcodec_send_packet (ffmpegdec->context, NULL))
     goto send_packet_failed;
 
-  do {
-    got_frame = gst_ffmpegauddec_frame (ffmpegdec, &ret, &need_more_data);
-    if (got_frame)
-      got_any_frames = TRUE;
-  } while (got_frame && !need_more_data);
+  /* FIXME: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1474 */
+  if (!(ffmpegdec->context->flags2 & AV_CODEC_FLAG2_SKIP_MANUAL)) {
+    do {
+      got_frame = gst_ffmpegauddec_frame (ffmpegdec, &ret, &need_more_data);
+      if (got_frame)
+        got_any_frames = TRUE;
+    } while (got_frame && !need_more_data);
+  }
   avcodec_flush_buffers (ffmpegdec->context);
 
   /* FFMpeg will return AVERROR_EOF if it's internal was fully drained