How does AVCHD differ from H264?

[Paul Cascio]

I have a little Sanyo HD2000 that shoot great images, but records to H264, and an HMC150 that is AVCHD. Can someone explain if these are totally unrelated formats, or just wrapped differently? I one better than the other, or easier to edit? I fugure I will transcode before editing.

[Brian Boyko]

Originally Posted by Paul Cascio

I have a little Sanyo HD2000 that shoot great images, but records to H264, and an HMC150 that is AVCHD. Can someone explain if these are totally unrelated formats, or just wrapped differently? I one better than the other, or easier to edit? I fugure I will transcode before editing.

AVCHD is a standardized type of H.264 which includes metadata, thumbnail images, etc, in a specialized file system.

If you were to open up the file system on your HMC150, and copy the files from the "Stream" directory to your hard drive, those files on your hard drive would be H.264, but they would not be AVCHD.

The main difference between the two tends to occur only when logging, as if your capture/copying software supports AVCHD, you can keep the files labeled by time and date shot. Otherwise, the default is 00001.mts, 00002.mts, etc.

[Paul Cascio]

Terrific explanation Brian. Thank you.

[Nick Gordon]

Another thankyou

[Jeff Kellam]

To add a little further clarification, the 150 shoots in the high level variant of H264 and the Sanyo shoots in the main level variant of H264.

[Paul Cascio]

True Jeff. I've got to say however that I am totally impressed with this little, $600 Sanyo. It's got full manual control, mic and headphone jacks, can shoot low-res 600fps slo-motion, and 1080/60p. The lens it quite good and the images are awesome. The OIS is not very good and the image seems a bit saturated. Also, the pistol form factor takes getting used to, but can be very useful in certain situations.

Here's a very basic test clip,which is also my first ever Vimeo upload. It's unretouched but was rendered to WMV.

http://vimeo.com/5452376

[Ronald Lee]

Actually, that explanation didn't answer the OP's question.

Which is easier to edit with? I know, the reply was depends what your editing software takes. But what if it takes both? I'm probably going to upgrade to Premiere CS4 and I can't imagine it being able to only edit one of the two.

And this camera, the Sony HDRXR100 has these stats:

Video Resolution 1920 x 1080
Video Format MPEG4 AVC/H.264, MPEG2

Does this mean that this camera is switchable between AVC and H.264 or they are the same thing? I'm confusion AVC with AVCHD?

Sorry for the ignorance, I'm just coming back to camcorders after a hiatus.

[David Kennedy]

I'm shooting the 150 and am barely successful in editing in CS4. Should I re-code to another file format, or do this:

"If you were to open up the file system on your HMC150, and copy the files from the "Stream" directory to your hard drive, those files on your hard drive would be H.264, but they would not be AVCHD."

What would be easiest to edit?--thanks,

[Paul Cascio]

Yes, from everything I learned on this forum, it's definately advisable to transcode to Cineform or even straight AVI (uncompressed) rather than editing in the native AVCHD, or H264, which is AVCHD (Stream Folder) without it's accompanying metadata info.

This will speed editing and preserve quality, especially if you are using effect or transitions of any kind.

Cineform's NEOScene costs about $129 and it's a worthwhile investment.

[Ronald Lee]

"or even straight AVI (uncompressed) "

That would take a lot of space!!! Can it be converted to NTSC-DV or something manageable?

[Paul Cascio]

Sure, if your deliverable is SD, but you'll only need the drive space temporarily. Once your project is done you can delete them. You'll retain your original AVCHD files as your archive.

An intermediate format such as Cineform, really offers a better solution - the files aren't as big as uncompressed AVI, and they retain the quality. Also, the conversion is very quick using NeoScene.

[Bryan Sellars]

I think if you use an editing program with the ability to make proxy files it makes Cineform unnecessary but having said that if you do use Cineform it does an excellent job.

[Jonas Marlowe]

Originally Posted by Bryan Sellars

use an editing program with the ability to make proxy files .

what program would that be?

[Bryan Sellars]

I use Corel Pro X2, my video camera is a Canon HF10 AVCHD 1920x1080/50i I set the Proxy files to 720x576 on my main computer a 3GHz dual core and on my lap top a 2,2GHz dual core I use 352x240.

[Dave Haynie]

There are two issues... the video/audio itself, and the "wrapper".

The Sanyo is using the MPEG-4 file format (.mp4), which is a relative of Quicktime's object oriented file format. AVCHD is defined to use the MPEG-2 transport stream format, the same file format (but different contents) you get from a direct HDV camcorder capture.

Difference #1 is the audio: Sanyo is recording in the compressed AAC (Advanced Audio Coding) format, also sometimes called "MPEG-4 audio". This is the same format standard for iPod audio. AVCHD uses AC-3 audio, also called Dolby Digital (AC-3 is a SMPTE standard), same as typically used on DVD.

There are also file structure issues... sort of. Sanyo defaults to a single subdirectory on an SD card, pretty much the same you'll find with digital still cameras. AVCHD is derived from the Blu-Ray standard, and at least some AVCHD camcorders create a whole Blu-Ray-like directory structure. These issues only matter when you're trying to find video files to copy over. You can find out details on this here: AVCHD - Wikipedia, the free encyclopedia

AVC (Advanced Video Coding) is the same as H.264 is the same as MPEG-4 Part 10. Like most specifications maintained by the MPEG people, this is not usually a final specification in itself, but used to create other specifications (for example, the MPEG-2 technologies lead to DVD, DVB, HDV, and ATSC formal specifications).

Sanyo's format is really a spec unto themselves.. think of it as "generic" MPEG-4 video... the file format, AVC video, and AAC audio are all part of the MPEG-4 specification. Technically, I believe this is the Main-Profile@Level-4.2 spec of the AVC standard. The specific limits are up to Sanyo, but at 1080/60p, you see variable bitrate AVC peaking close around 28Mb/s, but supposedly averaging at 24Mb/s.

AVCHD is a spec cooked up by Panasonic and Sony, which again, is derived from Blu-Ray as a similar camcorder format, for use on computer media (disc, HDD, flash). By specification, AVCHD supports High-Profile@Level-4.1 AVC, though most of the consumer cameras until recently have used Main-Profile@Level-4.0, usually limited to 17Mb/s.

Panasonic's AVCCAM is a professionally oriented version of AVCHD, which supports High-Profile@Level-4.1 AVC at up to 24Mb/s. Panasonic has been using Main-Profile@Level-4.0 up to 17Mb/s in all of their consumer models, far as I know. Canon, however, has been supporting the 24Mb/s and high profiles in their recent camcorder models.

There's also a thing called AVCHD-Lite, which supports AVC encoded video up to 720p only. This was introduced by Panasonic primarily as a format for video on digital still cameras.

High profile is more complex. It includes such buzzwords as "8×8 vs. 4×4 transform adaptivity", "Quantization scaling matrices", and "Separate Cb and Cr QP control ". Is also supports a monochrome mode, and 4:2:2 as well as 4:2:0 color modes.