G85

[Hubert Hofer]

I'm reading everywhere AVCHD is the better image to film in. The G85 & GX8 only have MP4 in 4k. My question is in this case would AVC full HD still provide a better image quality than MP4 ?

[Phil Lee]

Hi

Things like mp4, mov, avi, mpg are what are known as containers, they can contain anything basically.

AVCHD is a specification, a bit like Blu-Ray or DVD, it defines how the video is recorded so that all equipment that can play back AVCHD can do. AVCHD specifies some maximums, like the maximum bit rate and maximum resolution and frame rate that can't be exceeded.

The majority of cameras now can now easily exceed the bit rates and resolutions for AVCHD. This means if you want to playback and have compatibility straight from the camera to play on AVCHD equipment, the camera has to downsize and record at a lower quality.

4K is four times the resolution of the best of what AVCHD can be, and will use much higher data rates to capture that information. It puts it in an MP4 container as most computers and editing software know how to open that, and because it is a generic container that contain anything, it can hold 4K and higher data rates. It can't be called AVCHD because it way over that formats specification.

So the answer is in this case, the MP4 would contain considerably better quality than AVCHD as it is in 4K at higher data rates, which is four times the resolution of anything AVCHD can offer. Note that MP4 because it can contain anything of any quality, could be considerably worse than AVCHD, but in this case with this camera, it contains something much better.

Regards

Phil

[Hubert Hofer]

Hi Phil,
Thank you for your explanation. I will leave the cams on MP4 & be done with ith it. Got some very crisp footage the other day & I just got confused again (as usual) with all the facts & figures & a professional cameraman advised me to go with AVCHD. It's all just too distracting from concentrating on recording.
regards
HH

[Phil Lee]

Hi

I would stick with MP4, always better to capture the highest quality then downgrade if you have to have AVCHD when you render out from any editing software.

Regards

Phil

[Steve Burkett]

I confess to not being a fan of AVCHD. I heard it was better in low light than MP4, but never tested to confirm that. As a codec, it was more a pain to edit than 4K files. I actually had to transcode them for good playback in Premiere, whereas my 4K files I never did. Bitrate is usually low and I've only seen good stuff from it on the C100. Other cameras have not fared so well. The best thing leaving behind my GH2s was the fact I never had to work with AVCHD again.

[Phil Lee]

Hi Steve

AVCHD is essentially a brand name. It still contains video encoded using H264, as an MP4 would from the same camera. AVCHD just defines the maximum specifications of the video and types of audio it contains, the aim being AVCHD recorded on device A will play back on device B.

AVCHD has nothing to do with low light ability. An MP4 recorded at the same bit-rate as AVCHD in the same camera would be very similar if not identical in quality.

I suspect the person who told you this was falling over video levels. MP4 on a camera is often recorded as full range 0-255 (this actually captures more colour information) whereas AVCHD would be 16-235, the TV range. Depending on the playback equipment or how the footage is edited, one may seem a lot darker and losing shadow detail than the other. So maybe it was this issue they had seen and were referring to.

Playback in editing packages and on PCs was always a bit harder for AVCHD, this was nothing to do with the video, you could for example with a bit of clicking and the right software convert AVCHD to MP4 with no re-encoding required, it is because AVCHD was designed for lossless editing in video cameras (which never really took off), and so was recorded with extra info to help with this, however software on PCs never really handled this too well and didn't always play it back smoothly.

For it's time it was pretty revolutionary, and brought us a non progressive 50/60P for first time as AVCHD Progressive in camcorders. It's now outdated of course.

Regards

Phil

[Hubert Hofer]

Thank you chaps, this is getting more interesting by the post.
I did quite a bit of MP4 recording in the past few days & the footage is great, I'm going to stick with MP4..

[Steve Burkett]

Cheers Phil for clarifying. With regards AVCHD and lowlight, I just recall it being something I read back when I got the GH3 in 2012, that if shooting lowlight, I'd be better off using AVCHD. I can't recall which website I saw this, but needless to say I never really took up the advice and stuck to MP4 as it offered a higher bitrate and I was too lazy to change settings during a shoot. Just as well.

I agree AVCHD is somewhat outdated. Shame I never knew there was a software trick to change the file to MP4. Still I shall bare this in mind for any possible future handling of it.

[Paul Cascio]

Phil, thanks for that enlightening explanation. I learned something today.