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Old 22nd March 2011, 11:16   #11  |  Link
eathasa
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Join Date: May 2006
Posts: 14
Hi roozhou --
What a helpful forum this is
Thank you for your work on the ffmpeg fork - it seems to be filling a hole!

I was finally able to mux a file that plays with the correct aspect ratio in all the players I tried -- yay!

I have some fairly minor concerns with the output from ffmpeg that I will explain to you .. but I will get back to you on that. I just spent a lot of time typing a message here detailing all that but accidentally hit a link with my mouse and when I hit "back" in my browser to get back to this thread, my detailed message was gone. :/...

One significant oddity/confusion for me was that the SAR had to be set to 3:4 to get my desired PAR of 3:4. I also used the aspect command line option to set DAR to 4:3 (I got inconsistent playback aspects in different players without that)

SAR × PAR = DAR (Pixel aspect ratio - Wikipedia)
DAR=4:3, PAR=3:4
Solving for SAR:
SAR = 4:3/3:4 = 16:9

The same Wikipedia article explains that SAR is simply the pixel ratio (pixels wide/pixels high); in my case:
SAR = 704:396 = 16:9

Does SAR have a different meaning to ffmpeg?
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