-
Blank spots after Rendering MPEG-2/ SONY AVC
Hi – every time I render a clip with audio there are intermittent blank spots that show up in the render. These blank spots are roughly about 1-2 frames and occur occasionally throughout the video.
They are not present in the footage (the source file / clip_ so the problem occurs strictly from the render.
Most of my individual clips on the timeline were MXF files that I converted into Quicktime MOV files.
My template settings: 1080-50i
Field order – Upper field
Pixel aspect rationL (square)
Pixel format 32bit.
Full resolution rendering quality: BEST
Motion blur type: Gaussian
Deinterlace method: Blend fields.
This problem ONLY ever happens when the audio is included in the CUSTOM / AUDIO / INCLUDE AUDIO setting in the CUSTOM SETTINGS tab.
When audio is not ticked (in the custom settings template) the blank spots do not show up on the render.
Please could someone tell me how to avoid these blank spots.
I have tried progressive scan, upper, lower, resample, disable etc.
It only seems to happen with the MOV files in my project.
Like I say, most of the files are MOV files.
Lastly, when I render WMV – MPEG4, these blank spots do not appear. But when I render with MPEG2 – Sony AVC, they turn up again in the same places.
Please give me some help.
Thanks in advance,
Anthony.
-
7 Replies
-
Have you imorted these files back into Vegas, zoom in and see if the frames are really black? Just to check if your media player may be the problem.
-
HI there – I came back here to say I had fixed the problem….after two days and hundreds of renders. I changed all the source media to upper field (some were progressive, some upper field) so I guess when it was rendering it was trying to compensate for the lost frame over time, hence the blank spot.
I haven’t rendered on MPEG2 yet, but it works on sony AVC now – which it didn’t previously, so it will probably work on MPEG2. If it doesn’t i’ll come back, but i’m pretty sure that it will be sorted.
Thanks 🙂
-
Actually – I spoke too soon. One rendering more of the film the problem occurred again!
I am really stumped on why it is doing it.
It seems that when I render longer clips – 4minutes onward – the two frame blank spots appear.
It’s not the source media because I have checked these frame by frame and rendered on WMV which is fine, as well as MPEG4 which is fine.
If I render those moments where the blank spots appear when I’ve rendered a longer portion of the film with this included, then they don’t show up.
Could having a mix of progressive source media, upper field source media lead to these blank spots occuring?
Please give me some suggestions on what to do….I am at my wits end.
I’m supposed to have a screening next month and time is running out for me.
Like I say, it’s only on MPEG SOny AVC that this problem occurs.
I don’t want to use WMV as I don’t like the compression – even on the best settings.
Thanks
-
I have encountered this and believe it to be a bug in the Sony AVC encoder. I get random black frames with Vegas Pro 10c. I cannot reproduce the problem with Vegas Pro 9.0e. I am using all progressive footage so it has nothing to do with field order. I would report it to Sony so hopefully they can fix it.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thanks for the reply – i’ve got a feeling you’re right. I’ve tried too many tests and variables. Still got one or two extra tests to try and take it from there. Worst scenario I render to MPEG4 which is still pretty good but annoyingly, not what I want to use!
I was considering using my older version 7.0 so i’ll maybe give that a shot if nothing else works.
I’ll let you know how I get on with these other tests – like you say though, they are random. I rendered the exact same clip from a shorter point in the film and the blank spots didn’t show. Then, when I rendered from further down the timeline, the blank spot showed up.
Just trying out different bit rates and a render from one big MOV file, as opposed to a timeline filled with individual MOV clips. See if that makes a difference.
-
This problem is still happening – I’ve narrowed it down to what seems to be the cause, possibly, of the problem.
When I render without audio there are absolutely NO blank spots.
When audio is included (include audio stream) the blank spots appear once again.
Any suggestions what to do to have the audio still on but to avert the blank spots? A different bit rate perhaps? Change a setting on the audio perhaps?
A strange one.
Please suggest ANYTHING that you may think will work.
My screening of my film is 10th June 🙁
Thanks.
-
Hi – just to say this was a bug with the software. I used Sony Vegas 7.0 and it’s perfect. Goes to show, older is sometimes better!
Reply to this Discussion! Login or Sign Up