Hi, I've been reading as much stuff as I can find what the best way to encode key frame aligned videos. Hopefully you can help me fill in the blanks.
1. Single or 2-pass encoding? I'm reading quality isn't affected much and that it may be possible to have aligned key frames with either one. What do you guys do? A blog I found says I can just use this: http://blog.streamroot.io/encode-multi-bitrate-videos-mpeg-dash-mse-based-media-players/ -x264opts 'keyint=24:min-keyint=24:no-scenecut' Wowza says to do 2-passes like this: http://www.wowza.com/forums/content.php?213-How-to-use-FFmpeg-with-Wowza-Media-Server-(MPEG-TS) ffmpeg -y -i bigbuckbunny_1500.mp4 -c:a libfaac -ac 2 -ab 64k -c:v libx264 -preset:v veryfast -threads 0 -r 24 -g 48 -keyint_min 48 -sc_threshold 0 -x264opts no-mbtree:bframes=1 -pass 1 -b:v 286k -s 384x216 bigbuck-350k.mp4 ffmpeg -y -i bigbuckbunny_1500.mp4 -c:a libfaac -ac 2 -ab 64k -c:v libx264 -preset:v fast -threads 0 -r 24 -g 48 -keyint_min 48 -sc_threshold 0 -x264opts no-mbtree:bframes=1 -pass 2 -b:v 286k -s 384x216 bigbuck-350k.mp4 ffmpeg -y -i bigbuckbunny_1500.mp4 -c:a libfaac -ac 2 -ab 64k -c:v libx264 -preset:v fast -threads 0 -r 24 -g 48 -keyint_min 48 -sc_threshold 0 -x264opts no-mbtree:bframes=1 -pass 2 -b:v 836k -s 640x360 bigbuck-900k.mp4 2. I want my videos to work on as many devices as possible of course. But I'm thinking of starting with 5 or 6 bit rates. We have only upto 720p sources and stream on a Wowza server. What bitrates do you stream? Apple seems to recommend 8 files https://developer.apple.com/library/ios/technotes/tn2224/_index.html#//apple_ref/doc/uid/DTS40009745-CH1-SETTINGSFILES Kaltura says you can get up to 40 if you have different files for desktop, iOS and Android. http://knowledge.kaltura.com/best-practices-multi-device-transcoding Google does 5 versions with live encoder and I'm liking this. I've seen they have 144p too on YouTube even though it's not listed. https://support.google.com/youtube/answer/2853702?hl=en TLDR; Single or 2pass for key frame alignment? How many files and at what bitrates is a good starting point for mobile and desktop? Thanks. _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user
