Bit rate choices for rendering in XAVC S

videoITguy wrote on 5/13/2014, 9:40 PM

What your question begs is a full understanding and appreciation of what XAVC S is actually supposed to be used for...please do some read and much homework.

"There are a few current flavors, or implementations, of XAVC. The first is full quality XAVC. This is a 1080p, 100mbps(at 30p, 200mbps at 60p), 4:2:2, 10-bit, Intra-Frame format. It’s extremely robust. It can also be 4K, 300mbps(at 30p, 600mbps at 60p), 4:2:2, 10-bit, Intra-Frame format.

There is another flavor that is very similar but it is Long-GOP. This is a 1080p, 50mbps(at 30p, 100mbps at 60p), 4:2:2, 10-bit, format. So you still retain much of the detail but you lose motion information. It can also be 4K, 150mbps(at 30p, 300mbps at 60p), 4:2:2, 10-bit. This flavor of XAVC hasn’t been put into use yet but it is expected to be made available as a firmware update to current XAVC hardware during 2014............

Sony's whole XAVC / XAVC-S overview was pretty well explained in their white paper release of 2013 called---

XAVC_SpecificationOverview_Rev2_130913.

This revision 2 release from Sept last I believe is the latest version. Quite an interesting read. See the document: entitled Sony XAVC_SpecificationOverview_Rev2_130913.pdf "

mark-rosenzweig wrote on 5/13/2014, 10:00 PM

Your answer is unhelpful, and also ignorant of both existing 4K cameras (e.g., the Sony AX100 and the Panasonic GH4) and the standards for XAVC S 4K. I have no interest in 1080. I was discussing XAVC S, not XAVC.

I want to output XAVC S 4K long GOP (same as the Sony AX100 puts out). In the current version of Sony Vegas Pro, there is no choice of bitrate in the rendering template for long-GOP, XAVC S 4K. Get it?

XAVC S 60Mbps long GOP is the Sony AX100 standard (8-bit 4:2:0). I want that as a rendering choice. Right now, the bitrate is over 100 Mbps. The Sony camera XAVC S bitrate is 60 Mbps. So 100Mbps is not a "standard."

John_Cline wrote on 5/13/2014, 10:14 PM

"Can I lower the rendering bitrate?"

No.

videoITguy wrote on 5/14/2014, 3:14 AM

If you looked up what you are asking - you would see that XAVC-S is Sony's flavor of XAVC for camera use - in other words optimization at the capture level. XAVC within NLE's from Sony and others is the standard codec interpreted for post work,

mark-rosenzweig wrote on 5/14/2014, 5:35 AM

XAVC S (long-GOP) 4K is offered as a delivery codec in Vegas Pro. XAVC S 4K is 60 Mbps in the AX100 Sony camera. It is defaulted to 100+ Mbps in Vegas Pro. That's seems completely arbitrary.

So, as I surmised and is confirmed, there is no bit-rate choice in Vegas Pro for XAVC S and it is larger than the standard XAVC S used in the AX100.

That is a shortcoming of the program, especially given that the two most popular sources of 4K video have bitrates (and similar 8-bit, long-GOP codecs) that are less than 80 Mbps. These are the Panasonic GH4 and the Sony AX100.

John_Cline wrote on 5/14/2014, 7:19 AM

60 Mbps was chosen for the AX100 due to the fact that it is about as high a bit rate as they can safely record to a Class 10 SD card. 4k video at only 60 Mbps seems like somewhat a compromise to me, of course, the compromise probably also extends to the limitation of only being able to shoot at 30P maximum. From an image quality standpoint, 4K-30p @ 100 Mbps seems like a more reasonable bit rate.

mark-rosenzweig wrote on 5/14/2014, 7:26 AM

I agree with your speculation. However, with a 60Mbps or 80 Mbps input video (AX100 and GH4), there is little point to rendering at 120 Mbps (what I am seeing).

Surely you are not arguing that having no choice of rendering bitrate is a desirable feature? File sizes for uploads matter, and the Ax100 original videos show that 60 Mbps does an excellent job. Increasing files sizes by 100% over the originals (same exact codec for the Sony AX!00) is not efficient from a quality/size perspective.

videoITguy wrote on 5/14/2014, 8:59 AM

markr041, have you looked at what is happening during 'smart-render'
Xavc-S - 60 from camera to timeline - edits made, then render to Xavc-S - 100 , do you find that you are smart rendering in VegasPro13? or render to Xavc - is it smart rendering?

mark-rosenzweig wrote on 5/14/2014, 10:10 AM

"markr041, have you looked at what is happening during 'smart-render'
Xavc-S - 60 from camera to timeline - edits made, then render to Xavc-S - 100 , do you find that you are smart rendering in VegasPro13? or render to Xavc - is it smart rendering?"

Vegas Pro 13, unfortunately, definitely does not smart render XAVC S long-GOP 4K files. There is smart rendering of some 4K XAVC variants (maybe intra), but not the 4K video from the AX100.

Eric_SCSDev wrote on 5/14/2014, 11:05 AM

Hi everyone,

I just wanted to clarify a few items about XAVC and XAVC S and Vegas Pro 13. First, XAVC and XAVC S are both Sony Formats, and both are based on (and compliant with) the H.264/MPEG-4 AVC format.

The primary differences are simply:

XAVC uses the MXF wrapper, supports resolutions up to 4096x2160 and 10-bit color, and supports Intra frame-only recording, as well as Long-GOP.

XAVC S uses the MP4 wrapper, supports resolutions up to 3840x2160 and 8-bit color. XAVC S supports only Long-GOP at this time.

Different Sony cameras use both XAVC (F55, F5) and XAVC S (AX100) as a recording format.

It is also correct that we currently do not provide a way to manually adjust the bitrate for XAVC or XAVC S renders. I understand that this is a desirable feature, and we are looking at the best way to add support for multiple or adjustable bitrate rendering.

Finally, the smart-render support is currently only for XAVC (Intra), not XAVC S.

videoITguy wrote on 5/14/2014, 3:52 PM

Thank you Eric-SCSDev , as these comments are welcome observations from the development side and the information fills in some of the gaps in previous released Sony white papers on this subject. Always good to communicate the full score - so the user community is really aware!

4krevolution wrote on 5/16/2014, 3:46 PM

The ability to choose the bitrate for rendering XAVC-S, as well as smart-render, would indeed be very appreciated. I would like to render/smart-render my FDR-AX100 videos at their original 60Mbps.

Also for youtube/vimeo I don't know what is the exact cutoff for 4k but I think it's around 15Mbps. Ie if you upload H.264/MPEG-4 AVC at up to 15Mbps I think they won't compress it further (for 4k streaming) and hence it will display it as it was uploaded. Or maybe now this would have to be done with their royalty-free VP9 codec?

Unless youtube/vimeo have stated that they store the original uploaded videos (at 60+ Mbps) to use them later when new codecs become standard?

AlfAa wrote on 5/6/2015, 11:54 AM

Hello, it's been almost a year since this reply. I am specifically interested in this:

"It is also correct that we currently do not provide a way to manually adjust the bitrate for XAVC or XAVC S renders. I understand that this is a desirable feature, and we are looking at the best way to add support for multiple or adjustable bitrate rendering."

So, anything ever happen on this? I have Sony Vegas 12 and if I need to upgrade in order to be able to adjust bitrate rendering, I am ready to do so.

balazer wrote on 5/6/2015, 2:04 PM

XAVC and XAVC S are not general purpose formats. They are specifically for capture and interchange. The bit rates Sony has chosen are sensible for those purposes.

If you need different bit rates, you'll have to use the Mainconcept AVC or Sony AVC compressors. Though those compressors both have their issues, and I generally prefer to use XAVC S, which supports high bit rates and has been reliable for me.

If you really need fine control over how your compressed output is written, the best thing is to write to uncompressed YUV AVI and then compress using ffmpeg.

AlfAa wrote on 5/6/2015, 2:26 PM

Thanks, that is helpful.

The reason I ask about the XAVC and XAVC S formats is because I own a camcorder produced by Sony, an FDR-AX100, that produces raw content at a bitrate of about 55kbps. The only templates I see in Vegas 12 that are set up for 3840x2160 are the XAVC and XAVCS ones, but they do not allow one to alter the bitrate, which seems to be set at about 114kpbs. Doubling the bitrate in the render in my case, as we all know, would needlessly increasing the site of the output file without increasing quality ...

So it sounds like I should just need to create my own custom template, accounting for the frame size, desired bitrate, etc. using Mainconcept AVC or Sony AVC ... will do ...

zipzap wrote on 9/7/2015, 11:33 AM

I too have a Sony AX100. The files in their original XAVCS 100mbs format play perfectly from a USB drive on my Panasonic Viera TX55CX802B . However, once edited and rendered out to the pre-set - XAVC S Long 3840x2160, the files won't play! Has anyone any idea how to solve this?

OldSmoke wrote on 9/7/2015, 1:17 PM

I render all my AX100 files to XAVC Intra first, I use Catalyst Prepare as those play much better on my system. Once edited, I save them as XAVC Intra too.

zipzap wrote on 9/7/2015, 5:02 PM

Thanks Old Smoke. Tried your suggestion. Sadly neither the original file converted to intra in Catalyst Prepare nor that conversion then edited and rendered in Vegas 13 work on my Panasonic TV. It doesn't even see the .mfx files - let alone show them as video files, which it then can't play!

OldSmoke wrote on 9/7/2015, 5:56 PM

Sorry, I missed the part where you mentioned that you want to play them on your TV. XAVC is not really meant for playback. For playback on TV I frame serve to Handbrake to get a playable MP4 file at a much lower bit rate. Do a search for "Vegas to Hamdbrake" in this forum. I bit of work to get it all setup but well worth it.

Edit:
You can also try and run the XAVC-S MP4 file through Handbrake before you go through the whole Vegas2Handbrake setup; but not the MXF file.

zipzap wrote on 9/7/2015, 8:52 PM

I'd already done a Handbrake render, but of course it's not 4K - nowhere near.

It's a shame that Sony Vegas can't create an edited render in the same format that the 4K Sony Camera outputs! I bought the 4K Camera so that we could watch our daughter on a 4K TV. My mistake!

OldSmoke wrote on 9/7/2015, 8:56 PM

I'd already done a Handbrake render, but of course it's not 4K - nowhere near.

It is 4K and you can get same quality. I render via HB to 20-25Mb 4K and it looks as good as the one from the camera.

zipzap wrote on 9/7/2015, 9:28 PM

OK. I'll give it a try - tomorrow...
Thanks

Streamworks Audio wrote on 9/8/2015, 1:32 AM

Not sure if it has been mentioned here or not, but the AX100's latest firmware adds 100mbps to XAVC S. The camera itself can now do 100mpbs.

relaxvideo wrote on 9/8/2015, 2:05 AM

Great news for hard drive manufacters too! :)