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avformat/file: respect pkt_size even in streaming mode

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Also clarify the documentation a bit.

Signed-off-by: Marton Balint <cus@passwd.hu>
This commit is contained in:
Marton Balint
2025-12-30 02:36:04 +01:00
parent 38e89fe502
commit 8579037b6c
2 changed files with 18 additions and 12 deletions
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12
doc/protocols.texi
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@@ -354,13 +354,15 @@ overriding this might speed up opening certain files at the cost of losing some
features (e.g. accurate seeking).
@item pkt_size
Set the maximum packet size used for file I/O.
Set the maximum packet size used for file I/O. A smaller value may reduce
memory usage. A higher value may increase throughput especially with networked
filesystems.
For writing, this sets the size of each write operation. The default is
262144 bytes.
For reading, if explicitly set, it overrides the default internal buffer size
(32768 bytes) and limits the maximum amount of data read per operation.
Setting a smaller value may reduce memory usage when reading files sequentially.
(32 KB) and limits the maximum amount of data read per operation.
For writing, this sets the size of each write operation. The default is 256 KB
for regular files, 32 KB otherwise.
@end table
@section ftp

18
libavformat/file.c
View File

@@ -312,14 +312,18 @@ static int file_open(URLContext *h, const char *filename, int flags)
h->is_streamed = !fstat(fd, &st) && S_ISFIFO(st.st_mode);
/* Buffer writes more than the default 32k to improve throughput especially
* with networked file systems */
if (!h->is_streamed) {
if (flags & AVIO_FLAG_WRITE)
h->min_packet_size = h->max_packet_size = c->pkt_size ? c->pkt_size : 262144;
else if (flags & AVIO_FLAG_READ && c->pkt_size)
h->max_packet_size = c->pkt_size;
if (c->pkt_size) {
h->max_packet_size = c->pkt_size;
} else {
/* Buffer writes more than the default 32k to improve throughput especially
* with networked file systems */
if (!h->is_streamed && flags & AVIO_FLAG_WRITE)
h->max_packet_size = 262144;
}
/* Disable per-packet flushing by default to improve throughput especially
* with networked file systems */
if (!h->is_streamed && flags & AVIO_FLAG_WRITE)
h->min_packet_size = h->max_packet_size;
if (c->seekable >= 0)
h->is_streamed = !c->seekable;