gogro file converting?

[keithbt]

I have to convert my gopro mp4 files to avi files to edit them in wlmm and then i converted them back to mp4 and the quality is no where near the quality that comes right out of the camera...what am I doing wrong ?

 

[Marty Cerven]

Each time you convert unless using a loss-less codec your going to lose some quality, what bitrate settings are you exporting your AVI files in and then what is your final export file settings. Are you getting your AVI files from the gopro cineform software or with some other method?

I use adobe premiere pro cs5.5 for most of my editing and the advantage is that I just use the raw files in my timeline, then for my final export I set the file settings pretty much the same as the original gopro MP4 files. This gives me the best results but as you cant work with the MP4 files in your editing software, I only work with AVI files in 3D as I need the 3D files from gopro cineform to set 3D convergence settings.

If your not getting your AVI files from the GoPro software try to use that instead, then when exporting your final files try and set them at the same bitrate as the original files if possible. Lowering bitrate will greatly reduce quality the standard data rate of the HD formats on a gopro is 15mb/s so if your final export is much less then that it will always end up lower quality.

 

[dfx]

Note that in some cases it's possible to convert from one file format (more correctly: container format) to another without re-encoding the contained video or audio streams, thus the quality will remain unchanged. Under Linux I use ffmpeg and when I tell it to use a codec of "copy", it does just that. Under Windows, I believe you can use VLC to do the same thing (it uses ffmpeg behind the scenes).

However, after editing you'll still have to encode the streams somehow, so at that stage, make sure you're using high quality settings.

---------- Post added April 5th, 2012 at 09:48 AM ----------

If your not getting your AVI files from the GoPro software try to use that instead, then when exporting your final files try and set them at the same bitrate as the original files if possible. Lowering bitrate will greatly reduce quality the standard data rate of the HD formats on a gopro is 15mb/s so if your final export is much less then that it will always end up lower quality.

That's not necessarily true. The small cameras produce videos at such high bitrates only because they need to encode them fast (in real time). On a PC, you have the benefit of much higher processing power and the ability to encode at slower speed, which enables you to do much more aggressive encoding. H.264 has a ton of features that the camera doesn't make use of when encoding, but which you can use when encoding on the PC. Using those features, you can produce video at a greatly reduced bitrate (sometimes less than 10% of the original) without losing any quality, at the cost of a very slow and long encoding process.

 

[ronscuba]

....
That's not necessarily true. The small cameras produce videos at such high bitrates only because they need to encode them fast (in real time). On a PC, you have the benefit of much higher processing power and the ability to encode at slower speed, which enables you to do much more aggressive encoding. H.264 has a ton of features that the camera doesn't make use of when encoding, but which you can use when encoding on the PC. Using those features, you can produce video at a greatly reduced bitrate (sometimes less than 10% of the original) without losing any quality, at the cost of a very slow and long encoding process.

There are so many encoding settings you can go mad experimenting with all the different options. In my experience, if video quality is your goal, keep the encoding settings as close as possible to the original.

 

[dfx]

There are so many encoding settings you can go mad experimenting with all the different options. In my experience, if video quality is your goal, keep the encoding settings as close as possible to the original.

That's what they invented encoding presets for. If you plan on uploading your HD video to some streaming provider (i.e. Youtube or Vimeo), you really have no choice, you have to get that bitrate down somehow, you can't expect people to stream video at 15 MBit/s. Either that, or trust the website to do the encoding, which will generally do a poor job on it.

Plus, you don't even know what the original settings were unless you do an in-depth analysis of the video stream. All you know is the bitrate and that doesn't really tell you anything. You don't know if B-frames were enabled, you don't know if trellis encoding was enabled, etc etc. Chances are that when you're encoding on the PC, you're already using at least some features that the original video wasn't using, thus producing a more efficient bitstream. With H.264, bitrate says absolutely nothing about quality. The savings in bandwidth are well worth a bit of experimenting and trial & error.

 

[ronscuba]

That's what they invented encoding presets for. If you plan on uploading your HD video to some streaming provider (i.e. Youtube or Vimeo), you really have no choice, you have to get that bitrate down somehow, you can't expect people to stream video at 15 MBit/s. Either that, or trust the website to do the encoding, which will generally do a poor job on it.
....

I thought Vimeo and Youtube encode whatever you upload regardless. At least it used to be that way. I'm satisfied how my vids look on Vimeo. It's not as good as the original, but for instant streaming over the internet, it's pretty good.

 

[dfx]

I thought Vimeo and Youtube encode whatever you upload regardless. At least it used to be that way. I'm satisfied how my vids look on Vimeo. It's not as good as the original, but for instant streaming over the internet, it's pretty good.

I don't know for sure about Vimeo, but at least on Youtube there's certain combinations of file/container format, codecs, bitrates, file sizes etc where it doesn't re-encode it. At least not for HD playback, it obviously still re-encodes it for playback at lower resolutions. Or I should say, that's how it was the last time I checked, which was quite a while ago, who knows what they're doing now. But yes, Vimeo generally does a better job at re-encoding stuff.

 

[Marty Cerven]

As far as I know both YouTube and Vimeo both re-encode any files you give them, there is no format you can upload to on youtube where it wont re-encode the video for streaming. I got this info from one of the head editors for GoPro themselves, the premium accounts like theirs get a premium 2 pass encode which is the main reason commercial accounts have much higher streaming quality then regular users on YT.

With Vimeo all plus account holders get their premium encoding process so it gets optimal stream quality, because of this I find its best to encode in the highest quality you can to give the online sites the most data to work with. Compressing no matter what always sacrifices quality, and its best to let the sites encoder do the compressing from my testing.

Id love to see you compress a raw GoPro file into a 1.5mbps file so 10% of original bitrate that has lost no quality, Its impossible Im sorry to say but If you can prove me wrong fair enough.

No streaming sites host uncompressed video but vimeo does offer a much higher data rate then what youtube does, plus they also allow users to download the original video if enabled.

 

[dfx]

Id love to see you compress a raw GoPro file into a 1.5mbps file so 10% of original bitrate that has lost no quality, Its impossible Im sorry to say but If you can prove me wrong fair enough.

That purely depends on the material. More details, more action = higher bitrate, less details = lower bitrate. Cameras ala GoPro produce videos with an almost constant bitrate, no matter what's going on in the picture, that alone should tell you that there's always a lot of bits wasted. Feel free to send me one of your source files and I'll see how small I can get it without noticeable quality loss (I don't have a GoPro myself and my Contour is in for RMA right now).