+static int request_frame(AVFilterLink *outlink)
+{
+ AVFilterContext *ctx = outlink->src;
+ AudioSurroundContext *s = ctx->priv;
+ int ret = 0;
+
+ ret = ff_request_frame(ctx->inputs[0]);
+
+ if (ret == AVERROR_EOF && av_audio_fifo_size(s->fifo) > 0 && av_audio_fifo_size(s->fifo) < s->buf_size) {
+ AVFrame *in;
+
+ in = ff_get_audio_buffer(outlink, s->buf_size - av_audio_fifo_size(s->fifo));
+ if (!in)
+ return AVERROR(ENOMEM);
+ ret = filter_frame(ctx->inputs[0], in);
+ av_audio_fifo_drain(s->fifo, s->buf_size);
+ }
+
+ return ret;
+}
+