[FFmpeg-devel] [PATCH] lavc/libvpxenc: prevent fifo from filling up

[David Lemler]

Prevent the fifo used in encoding VPx videos from filling up and stopping
encode when it reaches 21845 items, which happens when the video has more
than
that number of frames.

This problem occurs when performing the first pass of a 2-pass encode, as
otherwise, the fifo is properly drained, preventing it from overflowing.

Problem is fixed by manually draining the fifo when performing the first
pass
of a 2-pass encode.

Fixes the regression originally introduced in
5bda4ec6c3cb6f286bb40dee4457c3c26e0f78cb

Signed-off-by: David Lemler <david at lemler.family>
---
 libavcodec/libvpxenc.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavcodec/libvpxenc.c b/libavcodec/libvpxenc.c
index 8833df2d68..e4ab13e6ab 100644
--- a/libavcodec/libvpxenc.c
+++ b/libavcodec/libvpxenc.c
@@ -1452,6 +1452,12 @@ static int queue_frames(AVCodecContext *avctx, struct
vpx_codec_ctx *encoder,
             memcpy((uint8_t*)stats->buf + stats->sz,
                    pkt->data.twopass_stats.buf,
pkt->data.twopass_stats.sz);
             stats->sz += pkt->data.twopass_stats.sz;
+            /* Drain the fifo if it has any items in it to prevent it from
+               filling up when performing the first pass of a 2-pass encode
if
+               the video has more than 21845 frames. */
+            if (av_fifo_can_read(ctx->fifo) > 0) {
+                av_fifo_drain2(ctx->fifo, 1);
+            }
             break;
         }
         case VPX_CODEC_PSNR_PKT:
-- 
2.41.0.windows.1