Render to Sony AVC always stops at 4,194,444 KB

ojpt wrote on 9/30/2010, 11:19 AM

I have a 45 minute composition in 1080p 23.976. I'm attempting to render to Sony AVCHD 1280x720p 23.976 at a bitrate of 15mbs to an MP4 file in 'Best' quality. Audio is set to either AAC or uncompressed. The source footage is in Cineform HD 1080p 23.976. The only effect I've used is Color Curves and any Jpegs on the timeline are resized to 1280px maximum dimensions.

The render errors out saying "an error occurred while creating the media file ... the reason for the error could not be determined." The rendered MP4 file is unplayable and always the size is 4,194,444 KB. Usually it takes my system around 6 hours to reach that point.

All of my disks are NTFS. Dynamic RAM preview is set to zero. I am able to render successfully using the included MainConcept MPEG2 and also to HDV and to AVI DV. The resulting MPEG2, HDV and DV files are very large, over 4GB.

I've also tried tweaking the frame size to 1080p or setting entropy encoding to CAVLC or rendering without audio...but the result is the same. Also, rendering a 10 minute excerpt of the composition is successful.

Am I running into a known limitation here or am I doing something wrong? Anyone know of workarounds that will allow me to output at the native framerate of 23.976p?

thanks,
--OJ

Comments

Eugenia wrote on 9/30/2010, 4:42 PM

You're probably running to some internal Sony AVC limit at 4 GB. I suggest you just export as MP4 (don't use the AVCHD templates, which do have 4 GB limits usually), with less bitrate. If possible, if you're using Platinum 10, use Main Concept, you can export at 8 mbps average, and 16 mbps Max (VBR). For 720p, this is more than enough bitrate, and it will create a much smaller file than 4 GB. Always use AAC for finalized audio btw.

ojpt wrote on 10/6/2010, 2:41 PM

Hi Eugenia, thanks for your help. =)

I'm using VMS 9 Platinum, which doesn't have the customizable MainConcept AVC codec. So, I tried to lower my bit rate to 8 mpbs in Sony AVC (720p 23.976). The render did complete without error resulting in a file of nearly 3 GB. However, curiously the MP4 file is unplayable. WMP and QT both say the file is not a recognizable type. Very odd.

So, it looks like there could be something about my composition that Sony AVC does not like regardless of bit rate or file size. AND also, as Eugenia suggested, there may be a 4 GB output limitation built into Sony AVC (can anyone confirm this?). I'll have to run more tests with a completely "clean" composition to verify these results.

For now I've worked around it by instead rendering to a 24p 25mbs 1080p MPEG2 video stream (MainConcept blu-ray preset) and muxing the audio in Avidemux. Resulting file is *huge* and looks great.

For deliverables where MP4 AVC is required, I am exporting an intermediate file from VMS and then transcoding to AVC inside of Avidemux. This takes a long time but the final video also looks great.