[FFmpeg-devel] [PATCH v3 2/2] lavf/mpegenc: fix termination following a fifo overrun

Nicolas Gaullier nicolas.gaullier at cji.paris
Tue Mar 22 18:39:11 EET 2022


Avoid an infinite 'retry' loop in output_packet when flushing.

A fatal error mentions the availability of fifo_size_limit option.

Signed-off-by: Nicolas Gaullier <nicolas.gaullier at cji.paris>
---
 libavformat/mpegenc.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/libavformat/mpegenc.c b/libavformat/mpegenc.c
index 5d755e3bdd..eff4531037 100644
--- a/libavformat/mpegenc.c
+++ b/libavformat/mpegenc.c
@@ -85,6 +85,7 @@ typedef struct MpegMuxContext {
 
     int preload;
     uint32_t fifo_size_limit;
+    int fifo_size_exceeded;
 } MpegMuxContext;
 
 extern const AVOutputFormat ff_mpeg1vcd_muxer;
@@ -1153,7 +1154,7 @@ static int mpeg_mux_write_packet(AVFormatContext *ctx, AVPacket *pkt)
     StreamInfo *stream = st->priv_data;
     int64_t pts, dts;
     PacketDesc *pkt_desc;
-    int preload;
+    int preload, ret;
     const int is_iframe = st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
                           (pkt->flags & AV_PKT_FLAG_KEY);
 
@@ -1220,10 +1221,17 @@ static int mpeg_mux_write_packet(AVFormatContext *ctx, AVPacket *pkt)
         }
     }
 
-    av_fifo_write(stream->fifo, buf, size);
+    ret = av_fifo_write(stream->fifo, buf, size);
+    if (ret == AVERROR(ENOSPC)) {
+        s->fifo_size_exceeded = 1;
+        av_log(s, AV_LOG_FATAL, "Input stream buffer overrun. "
+                "To avoid, increase fifo_size_limit option.\n");
+    }
+    if (ret < 0)
+        return ret;
 
     for (;;) {
-        int ret = output_packet(ctx, 0);
+        ret = output_packet(ctx, 0);
         if (ret <= 0)
             return ret;
     }
@@ -1231,9 +1239,13 @@ static int mpeg_mux_write_packet(AVFormatContext *ctx, AVPacket *pkt)
 
 static int mpeg_mux_end(AVFormatContext *ctx)
 {
+    MpegMuxContext *s = ctx->priv_data;
     StreamInfo *stream;
     int i;
 
+    if (s->fifo_size_exceeded)
+        return 0;
+
     for (;;) {
         int ret = output_packet(ctx, 1);
         if (ret < 0)
-- 
2.34.0



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