Media Encoder adds thin green line on FLVs

Question

I am using Adobe Media Encoder CS5 to convert .mov files to .flv files. When I render the files a thin (~2 px) green line appears on the bottom of the video.
When I used Media Encoder to format into F4V the line does not appear. See image below for example. Both files were encoded using the same Instance of Media Encoder and the same source file.
Things I have tried
I have tried encoding without resizing the video (Native 902x507)
I have tried resizing to make sure video dimensions are divisible by 4 (904x508)
I have used both CBR and VBR have same effect
I have changed bitrate to higher with same effect
Note:
The source video does not have the green line
System:  Windows 7 64x - 8GB RAM
Source video
format:*.MOV, codec:H.264, size:902x507, framerate: 29.97 fps, Data rate: 6.82 mbits/sec
Any suggestions on how to remove this?

Answer 1

I set up some quick tests and found that yes, transcoding a 902x507 H.264-encoded QuickTime file to FLV with AME 5.0.2 causes a green horizontal line.  It occurs at line 507, but doesn't go all the way across.  If I use the Crop option to trim off the bottom pixel of the source, the green line still occurs, but this time at line 505.  The difference is due to the scaling that AME is adding to the render process when Crop is turned on.
A little sleuthing reveals:
1) A 902x507 QuickTime file encoded with the Animation codec does not cause this problem.  This tells me the cause of the problem is in the H.264 decode, not the FLV encode.  It probably doesn't show up in the F4V encode because F4V is H.264 with a Flash wrapper, thus not much transcoding is actually being done.  Transcoding to other formats has the same problem, though.
2) The output dimensions of the FLV are 912x512.  This is despite that AME shows the settings for the export as 902x508 (or 902x506 with the pixel trimmed from the bottom).  The FLV exporter appears to be rounding up to the nearest value that is evenly divisible by 16.  This is a bug, but has already fixed for a future release of AME.
I had success using the Crop option to trim the size of the source file to 896x496 (the next multiple of 16 down).  Take 3 pixels off both the left and right, 6 pixels off the top, and 5 pixels off the bottom.  I did not have success by changing the output dimensions directly to 896x496; this is because resizing doesn't trim pixels, it pads where necessary and retains all source pixels, including the "bad", odd-numbered line that is causing the problem.  Trimming them via crop is the only way to avoid having AME attempt to transcode those pixels.
Otherwise, I recommend you work around the problem by:
A) Going back to the media source and exporting a file that doesn't have an odd-numbered dimension.
B) Transcoding the file in another application to a different format (ex.: QuickTime with a different codec) or a non-odd-numbered dimension before using AME to transcode the file to FLV.
I am curious- what is the source of this QuickTime file, and why 902x507?  Those are unusual dimensions.