MP4 vs AVCHD

Kaiser

Mu-43 Regular
Hey guys and gals,

i'll be doing some video shooting on holiday soon and i plan to back up to my 128gb iPad. Ive since discovered that iOS cannot retrieve AVCHD files using the camera connection kit due to the AVCHD folder hierachy - it can only import from the DCIM folder.

So Ive noticed on my cams (GX7, EM1) that MP4 has lower bitrates than AVCHD. Am I giving up any quality by using MP4 ( which i can back up to the ipad ).
How do they compare for quality and flexibility of files in post. i will be using FCPX and at most some minor exposure adjustments and colour grading.

Thanks
 

GFFPhoto

Mu-43 All-Pro
I'm still fairly new to video, but my understanding is that AVCHD files are smaller so if space or long record times are an issue, use AVCHD, but otherwise use MP4 because they are much easier and faster to work with. And I've been told that they are fairly equivalent in quality.
 

T N Args

Agent Photocateur
GX7 uses variable bitrate recording, so bitrate tables are approximate only. The only exact correlation in my GX7 manual's table on AVCHD and MP4 bitrates is for 1920x1080 at 50p, where both formats are listed at 28 Mbps.

So I wouldn't worry about quality, but, as GFF says, the files will be bigger with MP4.
 

Kaiser

Mu-43 Regular
Thanks for the replies. Im only really making a short holiday video kind of a montage where each shot while probably only be 5-10 seconds or so. I'll have about 100Gb on the iPad for storage and Im taking 6 x 16gb cards so i can have two copies of everything. I just did a quick test in the backyard with some moving foliage and static objects. From my newbie eyes I couldnt discern any difference. What I could definately tell was which clip was taken with IBIS- :) Sure makes the videos look better with that 5-axis stabilisation.
 

Ellsass

Mu-43 Regular
Try editing a few test clips before your trip. AVCHD is much more diffcult to edit (or at least it used to be). Everything can play and edit MP4 with no problems.
 

edwardconde

Mu-43 All-Pro
I would recommend looking at something like http://www.amazon.com/RAVPower®-FileHub-Wireless-3000mAh-External/dp/B00INMB23Q/ref=sr_1_1?ie=UTF8&qid=1402380024&sr=8-1&keywords=ravpower+filehub

Copy all the movie clips from SD to a usb hd. Use an app like FileExplorer on your iPad to create a NAS connection on . From there you will see all your clips on the HD. From there you can play and open the clips in iMovie or any other app that can play mp4. What this does for you is save the precious space on your iPad so you can work on the video…

I just did a quick test to confirm that this is possible…
 

speedandstyle

Mu-43 Hall of Famer
You can't just compare bit rates unless you are simply talking about how much storage you need.

I don't think one is really "better" than they other. They differ in how they compress and store the data. If you want to look at your video and store and/or edit it on your iPad then MP4 is the way to go.
 

Kaiser

Mu-43 Regular
Thanks all. While Id love to try out the wireless RavPower thing- I already have too many gadgets/chargers etc, and I dont think Id be able to acquire one before I leave anyway. Guess I'll roll with mp4 as its easier to store on the ipad. Cheers.
 

TonyZhang

Mu-43 Regular
While I can't speak for the EM-1, which is relatively weaker in the video codec department, the gx7 excels in both modes(I own a g6, but I have experimented with and seen many samples from the gx7, both cameras have the same video codec options). The approximate bitrate of the gx7 in both AVCHD and mp4 is 28mbps. However, in AVCHD mode, you have the option of 24p, which results in less compression every second, in mp4 mode, you are stuck with 1080 60p at 28mbps, so the bitrate of each frame is approximately halved. So if you were to shoot 24p in AVCHD compared to 60p mp4, you would get a cleaner image. However, in my experience, both codecs are very strong, and differences in codec and bitrate after editing and exporting are hardly ever noticeable unless you were to pixel peep very hard. I shoot mp4 because AVCHD, in my opinion, is a pain the neck, and with 60p, you have the option to slow footage down, which often helps stabilise handheld clips.
 
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