video conversion .mov to .flv BUT 416x234 pixel

[va7400]

Hello,
trying to upload a presentation video for a german exhibition. Original video format .mov and as a requirement of web server of exhibition, all videos must be in format .flv AND which is most difficult for me, they only accept
Video-Format: Flash (.flv), 416 x 234 px (16:9) otherwise the upload fails with error message, that video format does not match with requirements. Searching in web i have not found hits for 416 x 234 px (16:9)
I found many tools to convert .mov to .flv and this works fine, able to run the video with vlc player but i am unable to fullfill the requirement 416 x 234 px (16:9), so upload to exhibition web server fails
Any help would be welcome, thank you

[Selur]

Not sure where the problem really is, why not 'simply' resize to stay inside 416 x 234 and then add a letterbox to match the required 416 x 234 resolution? (should be possible with e.g. ffmpeg)

[va7400]

Hello Selur,
first of all, thank you very much for your answer. For sure, i am new in this arena. I followed your recommendation and ran
ffmpeg -i C:\1CD\AMBfilt.mov -f flv -s 416x234 -aspect 16:9 C:\1CD\AMBconv2.flv (can not test the result today, forgot login credentials for webaccess on my office desk at work)

Your answer sounds more like a two step solution. Do you suggest to first convert 1.mov to 2.mov by changing the size to 416x234 and then in a second step to convert format of 2.mov into 2.flv ?

Or what is the meaning of "letterbox" ?

Thanks

[Selur]

1. One command line call should be enough.
2. don't use '-aspect 16:9', 416x234 is 16:9 (no additional signalling needed)
3. letterboxing = process where you add black bars to a video to archive a specific resolution (normally you use the pad option for this); letterbox = the black borders that got added

here's an example, assuming the input had a resolution of 640x352:

ffmpeg -i "H:\TestClips&Co\test.avi" -vf scale=416:230,pad=416:234:0:0 -ar 44100 -f flv "h:\Output\test.flv"

scale=416:230 scales the input to width = 416 and height = 230 (= 416/640 *352 rounded to the next higher even number)
pad=416:234:0:0 adds black borders to the image to archive the wanted 416x234.
-ar 44100 makes sure the audio sampling rate it 44.1kHz

Depending on your start formats you might not have to reencode the audio and could use -acodec copy instead of '-ar 44100'.

Cu Selur

[va7400]

Thank you very much for help, was able to upload my files without problem. I was so curious for the result, so i organized the login credentials

Will try your fine tuning hints in a second attemp

Thanks a lot, problem solved

[Selur]

Main difference between you solution and mine is that I keep the aspect ratio, where as you distort the image (depending on your input resolution a bit or much), since you simply shrink to the target resolution without caring about the aspect ratio. -> if your input is already 16:9 the distortion is probably not really visible for most viewers.

Cu Selur