Massive virtual memory usage

[avramd]

Hello,

I don't know if this is a new problem, or if it's been happening all along, and I just had enough disk space & RAM that it didn't bite me.

Basically, I use a fairly routine process to transcode ripped DVD's; drop concatenated VOB file on ffmpegX, select "MP4 MOV", change aspect ration to "16:9 DVD", and press "Encode." Sometimes it works, sometimes it doesn't.

In recent efforts to determine what the difference is, I noticed that the "Progress" application is using crazy amounts of memory. It just sits there increasing it's VM size until it is done. From what I can tell, it may well be storing the entire movie in RAM until it has finished transcoding it. It appears to consume as much VM as the input takes up. That would mean that in order to compress a movie, I need twice as much disk space as the oringinal, plus however much the output file is going to take up.

This sounds extremely similar to what is going on in this post: https://www.videohelp.com/forum/viewtopic.php?p=1097963. However, in that case they believe that the issue has something to do with transcoding a movie with AAC audio, and that causing a need for two passes, and the whole thing being kept in RAM as a result. AFAIK, DVD's have mp3 audio, and I just did a test choosing the MP4/MOV preset, but then switching the audio encoding to MP3, and it is still eating VM like there is no tomorrow.

Well basically my mini can only have 1 GB of RAM, and it only has 6 GB of free disk space, and Progress keeps crashing, I can only assume b/c the underlying ffmpeg process is eventually being denied a request for more memory.

Is there any way to control or limit how much memory this thing consumes? There has to be a better answer than one process needing to simultaneously keep over 2 gigs of data in memory, this all should be getting written to disk as it goes along.

Thanks
Avram

[major]

I only observed this when decoding AAC (a fix has been implemented by using 'normalize audio'). If you have new data, please email me to major4@mac.com with screenshots, progress output, and sample files.

[avramd]

Hey Everybody,

Just thought I'd report that I "fixed" this problem. Major suggested I run the transcode in the terminal instead of in the Progress app, and it was immediately obvious what was wrong; basically every single frame was generating an error message. So, no, ffmpeg was not saving the movie in memory. But Progress was saving error messages that were in proportion to the # of frames in the movie. I've suggested that this is something worth wathcing for in future versions, and Major likes the idea.

In my particular case, there was a obviously a problem with the input VOB itself. It would have been nice for this to have been more obvious, and failing that, it would have been nice for it to at least have not made the computer unuseable (which is what it is when there is a single process using twice as much memory as is physicall available).