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AVI vs AVCHD quality
I recently purchased Sony HDR-CX7 (AVCHD format) along with Sony Vegas Pro to be able to edit the .m2ts files.
I also have Canon S3 still camera which has a movie mode in AVI format, using the M-JPEG codec. I never used the movie mode on the S3 and recently I gave it to my son who shoot some clips and asked me to edit them and put them on the web in WMV format. I did, and to my amazement I realized that the quality of AVI clips was far superior to the footage I could produce with HDR-CX7 in AVCHD format.
CX7’s video is good when played in it’s native Picture Motion Browser viewer but to make it usable anywhere else, especially on the web I have to either render it as WMV or MPEG-2 and that’s when it really looses to the quality I can get from a much cheaper still camera that shoots in AVI (Canon S3).
What gives? Is AVI the best format to convert to WMV and by definition the best format for the web production? Is there anything I can do to improve AVCHD -> WMV rendering while keeping the file size at the level of what I can get away with when rendering AVI -> WMV (1 Mbps)?
Should I just get another Canon S3/S5 just for shooting in movie mode (in AVI) because it really blows away CX7? Is that a crazy idea? I really don’t know what else to do — I’ve tried various rendering methods but nothing looks as good as what I get from AVI->WMV on the S3.
Thank you for your help.
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10 Replies
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Another way to phrase the question might be “which is better, paper bags or corn on the cob.”
You’re probably laughing, because this seems to be far out of context. It’s not.
AVI/Audio Video Interleaved, is a container. It can hold many different codecs including MPEG. AVCHD on the other hand, is a format, and can only be AVCHD, but could be packaged inside an AVI wrapper/container if someone wanted to go down that dev road. Seminar off…;-)
I assume by referring to “avi” what you really mean is “DV.” I would never consider taking a fairly highly compromised format such as AVC and converting it to DV for output to DVD. You’re crossing so many lines that shouldn’t/needn’t be crossed, but the big one is converting colorspaces three times when you don’t need to. The beauty of AVC is that it shares the same colorspace with DVD, so _no_ conversion is needed.
I’d respectfully submit the reason you’re seeing the differences in quality is a lack of understanding how the process works. Owning several CX7’s, an S3, and several other MJPEG-capable still cams, the still cam can’t really compete overall. But…if you’re converting to DV and using that as your comparison, then obviously you’re going to see some significant loss.
Compare the native AVCHD rendered to high bitrate WMV with the MJPEG-originated conversions to WMV, and you’ll find that the MJPEG is slower to render, and is of a lower quality.
You’re comparing 1440/1080 masters to 640/480 masters, and at 1MB, not sure if you’re uploading very high quality SD or fairly low quality HD, but in either event, the AVCHD master should generate a better overall image in this particular application.Douglas Spotted Eagle
VASSTCertified Sony Vegas Trainer
Aerial Camera/Instructor -
Another way to phrase the question might be “which is better, paper bags or corn on the cob.”
You’re probably laughing, because this seems to be far out of context. It’s not.
AVI/Audio Video Interleaved, is a container. It can hold many different codecs including MPEG. AVCHD on the other hand, is a format, and can only be AVCHD, but could be packaged inside an AVI wrapper/container if someone wanted to go down that dev road. Seminar off…;-)
I assume by referring to “avi” what you really mean is “DV.” I would never consider taking a fairly highly compromised format such as AVC and converting it to DV for output to DVD. You’re crossing so many lines that shouldn’t/needn’t be crossed, but the big one is converting colorspaces three times when you don’t need to. The beauty of AVC is that it shares the same colorspace with DVD, so _no_ conversion is needed.
I’d respectfully submit the reason you’re seeing the differences in quality is a lack of understanding how the process works. Owning several CX7’s, an S3, and several other MJPEG-capable still cams, the still cam can’t really compete overall. But…if you’re converting to DV and using that as your comparison, then obviously you’re going to see some significant loss.
Compare the native AVCHD rendered to high bitrate WMV with the MJPEG-originated conversions to WMV, and you’ll find that the MJPEG is slower to render, and is of a lower quality.
You’re comparing 1440/1080 masters to 640/480 masters, and at 1MB, not sure if you’re uploading very high quality SD or fairly low quality HD, but in either event, the AVCHD master should generate a better overall image in this particular application.Douglas Spotted Eagle
VASSTCertified Sony Vegas Trainer
Aerial Camera/Instructor -
Douglas,
You are absolutely correct — I should have used the term “AVI (Image: Motion JPEG; Audio: WAVE (Stereo))” throughout the post to avoid the confusion.
Nevertheless my Canon S3 blows away my CX7 — here’s a clip that was shoot using S3 (rendered in Vegas as WMV 640×480 at 1 Mbps bitrate — total 6mb file):
https://www.youtube.com/watch?v=KFHD9IY6Czk
Could you show me a comparable quality that came out of CX7 (on youtube) and hopefully explain how the heck do I get there from AVCHD? I will be the first one to admit that I know very little about video post-production — I shoot DSLR and only recently got into video, so please forgive my ignorance on this subject.
Thank you again for your help.
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If you were to look at youtube’s vassttraining channel, you’ll find several CX7 vids, but we don’t use wmv to encode for youtube. It’s a myth that WMV is best for youtube; we tested this extensively when working on our “Video for the Web” training DVD.
Again, you’re not comparing apples to apples, and bringing youtube into the mix only serves to confuse the discussion that much more.
On Vimeo, I have some 1280 x 720 streams that combine SD with HD. The HD is mostly AVC, and it’s pretty apparent (to me) when the timeline switches from SD to HD and back.
Douglas Spotted Eagle
VASSTCertified Sony Vegas Trainer
Aerial Camera/Instructor -
Ok lets forget youtube for a moment — here’s the same clip outside of youtube:
https://www.ttljournal.com/shooting-SW-460V.php
What do you think? Can you match this with AVCHD? 1 Mbps?
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yes, you can match that quality with AVCHD, but in a playable format. I quit watching the buffalo loads at 15 seconds, as I can’t bear stuttered, slow playing video, particularly when it’s Flash.
Again….you’re not making accurate comparisons. They are still both encodes to Flash.
Yet using Flash as the basis to support your point, you can still get a better/high quality encode from the AVC source.
A lot of people don’t understand downconverting and how to achieve it. It’s not an easy subject.
[edit] https://www.vimeo.com/1089994 is AVCHD source, it’s flash, it’s HD, and it plays on this fairly slow hotel connection.Douglas Spotted Eagle
VASSTCertified Sony Vegas Trainer
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I am on DSL and I couldn’t play it through without jitter and sound being broken up with pauses. But I will say that it’s the best one I’ve seen from AVCHD source.
The reason I am interested in web-based medium more than “playable format” is because I view the “playable format” as a print medium in still photography. Yes, there’s a place for it, but lets face it — if it’s on the web, more people will see it, and that’s what we want in this day an age. No one is sending each other DVD’s of their vacation videos and weddings. They post it once on the web and send a link to the video to dozens of friends who then send it to their friends etc.. You just can’t do that with hard medium (DVD).
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No one is sending each other DVD’s of their vacation videos and weddings. They post it once on the web and send a link to the video to dozens of friends who then send it to their friends etc.. You just can’t do that with hard medium (DVD).
You’re preaching to the choir here… 😉
https://www.vasst.com/product.aspx?id=99a9eab4-d26d-4968-a649-d5d5e2e40abchttps://www.youtube.com/watch?v=Lj16bBYFK5k
https://www.youtube.com/watch?v=g1uyvAYTXrI
There are also AVCHD comparisons on our YouTube channel. Aside from some proprietary practices that make minor differences, we simply encode to MP4 as our source. there are also comparisons between MP4 and WMV as source to Flash. They’re *very* close when encoded to the same rate Flash. WMV is slightly better for color, MP4 is slightly better for motion.
Douglas Spotted Eagle
VASSTCertified Sony Vegas Trainer
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Does your training video cover working with AVCHD as the source for the web? I have no problem spending the money and time on educating myself but I don’t want to go through all that only to find that I can’t apply it to AVCHD format. I rather shoot S3 :-), because I am pretty happy with the results as they are now.
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I think I finally figured out how to render Sony CX7’s AVCHD files for the web and keep the resulting file size at minimum. The trick is to convert AVCHD files to MPEG-2 using Picture Motion Browser software first. Next, edit MPEG-2’s in Vegas Pro and render the final project as WMV at 1 Mbps. The resulting file is small and quality is almost as good as the source MPEG-2.
I’ve tried working directly with AVCHD files in Vegas then converting them to WMV but the result is horrible IQ. I also tried rendering AVCHD as MPEG-2 in Vegas Pro but I can’t match the quality I get from Picture Motion Browser “Convert to MPEG-2 and Save” option.
The process adds additional overhead to the post processing workflow but I am willing to deal with it — the resulting quality is worth it.
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