+static int guess_channel_layout(MovieStream *st, int st_index, void *log_ctx)
+{
+ AVCodecContext *dec_ctx = st->st->codec;
+ char buf[256];
+ int64_t chl = av_get_default_channel_layout(dec_ctx->channels);
+
+ if (!chl) {
+ av_log(log_ctx, AV_LOG_ERROR,
+ "Channel layout is not set in stream %d, and could not "
+ "be guessed from the number of channels (%d)\n",
+ st_index, dec_ctx->channels);
+ return AVERROR(EINVAL);
+ }
+
+ av_get_channel_layout_string(buf, sizeof(buf), dec_ctx->channels, chl);
+ av_log(log_ctx, AV_LOG_WARNING,
+ "Channel layout is not set in output stream %d, "
+ "guessed channel layout is '%s'\n",
+ st_index, buf);
+ dec_ctx->channel_layout = chl;
+ return 0;
+}
+