Hi
considering my usual https://dl.dropboxusercontent.com/u/39871584/C0020.mxf
can I use ffmpeg to pass from HD (of course 16:9) to SD 16:9 and 4:3 (sd mxf= IMX D10 format of ffmbc)?
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Do you remember this thread?
https://forum.videohelp.com/threads/362968-ffmpeg-from-mp4-to-mxf
It's basically the same thing, piping ffmpeg to ffmbc
In ffmpeg, you need to deinterlace (double rate to 1080p50), progressive scale to SD, change to SD color (BT601), re-interlace; then that is piped to ffmbc to encode IMX50
Code:ffmpeg -i input.mxf -vf yadif=1:0,scale=720:576,colormatrix=bt709:bt601,interlace -pix_fmt yuv422p -an -f rawvideo - | ffmbc -f rawvideo -pix_fmt yuv422p -s 720x576 -r 25 -i - -tff -target imx50 -aspect 16:9 output.mxf
There is a new ffmbc out a few days ago synced to a more recent ffmpeg snapshot, but it needs to be compiled for windows. It might have SMPTE metadata timecode (ISMT) handling like current ffmpeg, and might have -vf interlace . If so, then you wouldn't need ffmpeg to pipe . Or newer ffmpeg builds might incorporate IMX preset in the future (then you wouldnt need ffmbc)Last edited by poisondeathray; 25th Apr 2014 at 18:50.
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I think he wanted 4:3 AR, so it will need to be cropped.
Out of curiousity, try this out:Got my retirement plans all set. Looks like I only have to work another 5 years after I die........ -
The 4:3 crop case is almost the same thing , just crop it to 1440x1080 before the resize , and change the -aspect 4:3 for the IMX50 encode. There are no special rules for horizontal cropping of interlaced material, so you can do it before the deinterlace (fewer pixels to process, thus faster)
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please I wonder: during HD-->SD conversion I loss quality? Or for better explain: if something needs to be broadcast in SD, should shoot directly in SD or HDtoSD conversion will produce SD worse results than shooting directly in SD
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It depends on many factors including, the camera, recording format. Some cameras do a poor job internally of HD=>SD. Some acquire at SD by subsampling the sensor, skipping lines/pixel binning, others do a proper resize
Almost always, a properly done progressive HD=>SD will yield better results, and gives you more options in post production and delivery. Interlaced HD=>SD conversions can be more tricky, there are other issues like aliasing, twittering . You can get worse results if not done properly
As always, you have to test your workflow and use what you think is better