[FFmpeg-devel] [PATCH 9/9] avformat/aviobuf: increase default read buffer size to 2*max_buffer_size for streamed data

Marton Balint cus at passwd.hu
Wed Sep 30 00:10:21 EEST 2020


This should increase the effectiveness of ffio_ensure_seekback by reducing the
number of buffer reallocations and memmoves/memcpys because even a small
seekback window requires max_buffer_size+window_size buffer space.

Signed-off-by: Marton Balint <cus at passwd.hu>
---
 libavformat/aviobuf.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index c4195e310b..15d91f91bc 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -938,6 +938,11 @@ int ffio_fdopen(AVIOContext **s, URLContext *h)
     } else {
         buffer_size = IO_BUFFER_SIZE;
     }
+    if (!(h->flags & AVIO_FLAG_WRITE) && h->is_streamed) {
+        if (buffer_size > INT_MAX/2)
+            return AVERROR(EINVAL);
+        buffer_size *= 2;
+    }
     buffer = av_malloc(buffer_size);
     if (!buffer)
         return AVERROR(ENOMEM);
-- 
2.26.2



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