Opened 5 years ago

Closed 5 years ago

#7865 closed defect (needs_more_info)

HLS_TEMP_FILE is not being set correctly

Reported by: kamyon Owned by:
Priority: normal Component: avformat
Version: unspecified Keywords: hls
Cc: Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no


I am using ffmpeg v4.1.3 to create an hls file locally. However, there seems to be an issue with checking the temp_file flag, and I get the "Cannot use rename on non file protocol, this may lead to races and temporary partial files" error, even though the output is a local file, and not a network url.

I looked at hlsenc.c to see what the issue may be, it seems there is a potential problem when checking whether the file is temporary or not. In the hlswindow function, line 1341 checks to see if a temporary file should be used by
int use_temp_file = proto && !strcmp(proto, "file") && (s->flags & HLS_TEMP_FILE);
The first two conditions evaluate to true, as they should, but the last condition (s->flags& HLS_TEMP_FILE) evaluates to false. I think this is a bug, since the flags to check should be the hls flags, not the format context flags (i.e., the last condition should be hls->flags & HLS_TEMP_FILE).

In my code, I use
av_opt_set(pFormatCtx->priv_data, "hls_flags", "+temp_file", 0);
to try to set this flag. When I verify that it is set by
assert(av_opt_flag_is_set(pFormatCtx->priv_data, "hls_flags", "temp_file"));
I can verify that it is being correctly set. However, it is not being picked up correctly. This may also be the same issue that was raised at

As a workaround/hack, I can set pFormatCtx->flags |= (1<<11), and then everything works correctly as much as I can tell, but this is obviously not a long-term solution (1<<11 is currently not any of the documented AVFormatContext flags).

Note that the same
int use_temp_file = proto && !strcmp(proto, "file") && (s->flags & HLS_TEMP_FILE);
line or similar is used in multiple lines in hlsenc.h, so this should (if it is a bug as I suspect) be fixed in those locations as well.

Change History (2)

comment:1 by Hendrik, 5 years ago

I believe this is already fixed in master.

comment:2 by Carl Eugen Hoyos, 5 years ago

Keywords: HLS_TEMP_FILE removed
Priority: importantnormal
Resolution: needs_more_info
Status: newclosed
Version: 4.1unspecified

Please test current FFmpeg git head and provide either an ffmpeg command line including complete, uncut console output or code that uses FFmpeg libraries and allows to reproduce the issue.

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