avformat/aviobuf: check if requested seekback buffer is already read

[ffmpeg] / libavformat / aviobuf.c

diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index 96754253497609c139a89960a560ce414346e58e..d94be478acc8d6fd5d2f5c8fbfe0f4eb09cd8146 100644 (file)
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -999,6 +999,9 @@ int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
     int filled = s->buf_end - s->buffer;
     ptrdiff_t checksum_ptr_offset = s->checksum_ptr ? s->checksum_ptr - s->buffer : -1;
 
+    if (buf_size <= s->buf_end - s->buf_ptr)
+        return 0;
+
     buf_size += s->buf_ptr - s->buffer + max_buffer_size;
 
     if (buf_size < filled || s->seekable || !s->read_packet)