A simple test... coverting h.264 to uncompressed, then back again. Help!

[squishy2011]

I'm kinda new at this- but I've been reading all weekend, so I hope I use the right jargon...

I have a video that I want to edit and export back to the same size and format. I'm having difficulty getting the size correct. The original file size is 7,849 KB. I am going to add a small PNG logo to the video (40kb as an overlay), and try to export back to roughly the same size.

First thing I noticed... the quality significantly goes down if I just edit and export using the same parameters/codec as the original video. I found that this is typical because I am attempting to re-compress a compressed video. The solution is to export the video to uncompressed PNG (about 1.5GB), then compress that back using the original codec. When I attempt to do this, the file size is no longer 7MB but instead 20MB. I've tried playing with quality settings, etc... but haven't found the magic combination that gives me roughly the same file size & quality. (turning the quality way down makes the file smaller, but it looks terrible).

Any advice you may offer would be much appreciated. Here are the video specs:

ORIGINAL VIDEO:

Wrapper: .MOV format (quicktime)
CODEC: H.264
SIZE: 854x480x24 (Don't know why it's not 720 but that's the size I received it).
LENGTH: 40 seconds long.
DATA RATE: 1429 kbps
TOTAL BITRATE: 1554 kbps
FPS: 29
AUDIO: AAC ,128k, stereo, 48kHz.

SOFTWARE I'M USING / HAVE TRIED:

Adobe Premiere Pro CS5
Pinnacle Studio 14 HD
Sony Vegas HD Platinum 10
Quicktime Pro

[Baldrick]

Can't you set the exact bitrate insted of quality settings? If not then try use mpeg streamclip.

[squishy2011]

Yes- a great starting place. I took the original uncompressed mov file and opened it in quicktime pro. Then I exported it using h.264 with the data rate set exactly to the same as the original. The output file was 8,238KB. So it was the closest yet- only 400K larger... but why? How come I cannot get it back down to 7,849? It's driving me nuts.

[Manusimon]

Your final video still has the 854x480x24 size?

[squishy2011]

Yes by that method it was 854x480. The problem comes into play when trying to edit the video.

When I add a small logo to the video then try to export, I get several problems:

1. If I export to a large, uncompressed AVI, then open that within Quicktime (so I can convert it to h.264), the video has a red background that won't go away. I've tried using other versions of quicktime, to no avail. There must be something in the Pinnacle Studio export software that makes some artifact that quicktime can't decode.

2. If I export the edited video directly from Pinnacle Studio HD15 (I upgraded to the latest version to see if that would fix the problem), and choose to export to H.264 codec, I get an "export failure (export plugin)". The reason was that the h.264 doesn't like odd sizes. It only works if you choose a "standard video size", i.e. 720x480, 1920x1080, etc. So the solution I chose was to just export the video to 720x480. It works, even though it looks a little "squashed".

3. If I export to a large h.264 file (1920x1080) and then open that file within Quicktime to export it to the size I need (854x480), I get these strange pixelation artifacts in the video. I've tried using higher data rates during export, upgrading to the latest (7.6.9) version of quicktime, but nothing seems to help.

So for now I will live with it at 720x480 but eventually I would like to find a solution to generate h.264 codec video at a custom size.

[squishy2011]

Yes by that method it was 854x480. The problem comes into play when trying to edit the video.

When I add a small logo to the video then try to export, I get several problems:

1. If I export to a large, uncompressed AVI, then open that within Quicktime (so I can convert it to h.264), the video has a red background that won't go away. I've tried using other versions of quicktime, to no avail. There must be something in the Pinnacle Studio export software that makes some artifact that quicktime can't decode.

2. If I export the edited video directly from Pinnacle Studio HD15 (I upgraded to the latest version to see if that would fix the problem), and choose to export to H.264 codec, I get an "export failure (export plugin)". The reason was that the h.264 doesn't like odd sizes. It only works if you choose a "standard video size", i.e. 720x480, 1920x1080, etc. So the solution I chose was to just export the video to 720x480. It works, even though it looks a little "squashed".

3. If I export to a large h.264 file (1920x1080) and then open that file within Quicktime to export it to the size I need (854x480), I get these strange pixelation artifacts in the video. I've tried using higher data rates during export, upgrading to the latest (7.6.9) version of quicktime, but nothing seems to help.

So for now I will live with it at 720x480 but eventually I would like to find a solution to generate h.264 codec video at a custom size.

Also note: I tried using mpeg streamclip, but it would lock up on me when doing conversion. I tried the stable release as well as the beta. My OS is Win7-64, which is supposed to be supported, but I don't think the software is very robust. Basically the software would put up a "processing" or "rendering" window, then do nothing. CPU usage of the process was at 0.

[guns1inger]

Your video isn't HD to start with. It is NTSC anamorphic widescreen resized to 1:1 pixel aspect ratio. Any attempt to resize it up to 1080p is going to result in a low quality file. I would suggest not using pinnacle at all. Even Vegas would be better. Output as uncompressed AVI, then use something like XmediaRecode to compress to H264 as an MP4 file. But I would not bother trying to get a 1080p output from that source. You simply don't have enough data to make it worth the effort.

[manono]

And the problems with the 854 width are due to it being Mod2. Maybe try 852.