ffmpeg.decode_audio cannot be run in parallel

[jheymann85]

To decode the input, the function writes the content to a temporary file. Its name is generated by the function GetTempFilename found in tensorflow/contrib/ffmpeg/default/ffmpeg_lib.cc. The template for the filename is %tmp_dir/tmp_file_%PID.%EXT.

When using multiple decoders in parallel this causes an undetermined behaviour since all decoders want to write and afterwards delete the same file.

A possible solution would be to use the thread id instead of the process id. I.e.

#include <sys/syscall.h>
#define gettid() syscall(SYS_gettid)
...
return io::JoinPath(dir, StrCat("tmp_file_", gettid(), ".", extension));

The first two lines are necessary because glibc does not wrap the call.

This solution works for me (on Linux). I'm, however, not sure if it works on all supported platforms. If that's fine, I can make a pull request.

[prb12]

@fredbertsch You are listed as owner for this contrib dir... could you please take a look?

[jonasrauber]

I also have this problem. Will you fix this?

[gunan]

@fredbertsch Any updates here?
Is this still a problem?

[rryan]

Just keeping folks in the loop, we have a candidate fix internally that @fredbertsch authored. Hopefully it will show up in master over the next day or two!

[fredbertsch]

A test and fix were added internally, and they should propagate here soon.

[tensorflowbutler]

It has been 14 days with no activity and this issue has an assignee.Please update the label and/or status accordingly.