Convert SONY AVCHD HD format to mp4 (720) in one step on Mac OS X

[BeardedPapa]

My new Sony FDR-AX33 camcorder’s native format is 4K, which we don’t need for our church youtube postings. To get the regular HD, it seems I have to use AVCHD format. The Sony software “PlayMemories” does a good job of exporting multiple (17 minute) files into one MTS HD file (1920x1080), but that still results in a huge file on my limited SDD memory on the Mac. I wish the software would let me export to the 720 size as well as mp4 in one step. But it doesn’t have that option.

If I use VLC or Movavi Video Converter, they can see the underlining files in the AVCHD folder, and convert them as desired, but for some reason, when I merge the 17 minute parts, the joining leaves a 1/2 second gap which I have to manually smooth out - as opposed to the PlayMemories export which seamlessly puts them together.

My workaround: use the USB cable to connect cam to mac and use PlayMemories to export to a SDD card, and then Movavi to convert the resulting MTS to mp4 of the 720 size. But that is so clumsy!

I tried the idea of a named pipe or fifo in Unix to hold the intermediate step, but that only works from the command line in a terminal. Sigh.

Any ideas without buying more software? Thanks. Boyd

[Case]

Recording
Video resolution
XAVC S 4K: 3840 x 2160/30p, 24p, XAVC S HD: 1920 x 1080/60p, 30p,
24p, AVCHD: 1920 x 1080/60p (PS), 24p (FX, FH), 60i (FX, FH), 1440 x
1080/60i (HQ, LP), MP4: 1280 x 720 30p

This seems to suggest that it would be possible to have the camcorder record in MP4 format with 720p resolution?

[Cornucopia]

I'm betting that the XAVC-S 1080p60 option would retain better quality for your youtube postings, and you would likely be able to retain single files, as you would be bypassing AVCHD's compartmentalized structure. And with ffmpeg, you could convert directly to another rez or format if necessary on Mac in one step.
But for goodness sakes, find a better app than "Play Memories" to do your work with. It's like using a toy hammer.

Scott