Hi,

Making a Blu-Ray Disk from Sony Camcorder files

No matter how I set the settings "auto" - or "Best Quality" - I get a quality setting of 63% (on a small 2 min clip)

Source .m2ts files are: 

Video
ID                               : 4113 (0x1011)
Menu ID                          : 1 (0x1)
Format                           : AVC
Format/Info                      : Advanced Video Codec
Format profile                   : High@L4.0
Format settings, CABAC           : Yes
Format settings, ReFrames        : 2 frames
Format settings, GOP             : M=1, N=26
Codec ID                         : 27
Duration                         : 51s 920ms
Bit rate mode                    : Variable
Bit rate                         : 16.0 Mbps
Width                            : 1 920 pixels
Height                           : 1 080 pixels
Display aspect ratio             : 16:9
Frame rate                       : 25.000 fps
Color space                      : YUV
Chroma subsampling               : 4:2:0
Bit depth                        : 8 bits
Scan type                        : Interlaced
Scan order                       : Top Field First
Bits/(Pixel*Frame)               : 0.309
Stream size                      : 99.9 MiB (93%) 

 

Why this reduced quality ?

Thanks

 

Hi.

That's because your source bitrate is 16 Mbps.

Read this KB : https://support.corel.com/hc/en-us/articles/216663727-63-Quality-Limit-When-Burning-To-Best-Quality-Blu-Ray-Disc-with-Studio

The KB article should clearly marked that it is for S15. I also think they are being somewhat creative with the facts.

In NGStudio you can put 12Mbps video on a disc timeline and produce 40Mbps discs, should you want to. In Studio 15 it was a programing limitation.

 

Thanks

If my source file is 16Mbps will I then get better quality producing a 40Mbps file ?

You won't improve the quality of the original file, obviously. You may make a marginal improvement to the quality of the export relative to one the encodes at 24mbps, but I doubt if you will spot that difference as the information that was thrown away by recording at 16Mbps isn't there to be degraded.

Cee5:

Thanks

If my source file is 16Mbps will I then get better quality producing a 40Mbps file ?

Impossible. The reason is Mathematics. The encoder can't create datas that are missing in your source file.

saby:

Cee5:

Thanks

If my source file is 16Mbps will I then get better quality producing a 40Mbps file ?

Impossible. The reason is Mathematics. The encoder can't create datas that are missing in your source file.

I think the question here is "If I re-encode a 16Mpbs file at 40mbps, with that look better that if I re-encode it at 24Mbps?"

Maybe. But my answer would be the same. 

 

saby:

Maybe. But my answer would be the same. 

My understanding is that an encoder can destroy data, even if it is using a higher bitrate than the source video. Otherwise it would be a lossless encoder.

So, I thought I'd run a test.

• Take a clip that was taken off air at around 12Mbps.
• Export it as an MTS file at 40 Mpbs, then re-load that and export it again.
• Repeat that 4 more times until I have a 5th generation file. (This just accentuates the errors, but there must be errors to accentuate.)
  
• Then start again and do the same process but with exports of 24 Mbps, resulting in a 5th generation 24 Mbps file,
  
• Find a frame that has fine detail and is also subject to movement (it's the movement details that get lost when you lower the bitrate).
• Take three snapshots and compare the differences.
• Zoom the snapshots into a small section to search for pixelation.
  

Now, if you study the attached photo, I think you can see that the 24 Mbps snapshot has degraded the detail more than the 40 Mbps snapshot. Yes - this is a very extreme test. But unless I've faked the photos or got my methodology wrong, I think that is proof that exporting a 12Mbps file to a 40Mbps file will produce a (ever so slightly) better result than exporting to a 24Mbps file.

So, "If I re-encode a 16Mpbs file at 40mbps, with that look better that if I re-encode it at 24Mbps?"

Let's have you final answer 

 

Ok, you score one point. But it's only half time, the match is not over. When I have time I'll dig out my old PSNR tools and see what several metrics say about your test.

 

thanks guys,

Sorry if my question was unclear.

It was a "What-if" question - wondering if setting "Best Quality" on my BD output - really gives me anything extra.

Interesting to see it can make a small difference - but in the overall - I dont think it matters so much for my home videos.

I did a small test.

I put a 37 sec clip on the timeline. .m2ts file recorded with my Sony camcorder - in best quality setting.

MediaInfo tells me :

Format                           : BDAV
Format/Info                      : Blu-ray Video
File size                        : 76.8 MiB
Duration                         : 37s 395ms
Overall bit rate                 : 17.2 Mbps
Maximum Overall bit rate         : 18.0 Mbps

Then I made 3 versions of a BD output from Pinnacle Studio14

Best Quality - 40Mbps:

Format                           : BDAV
Format/Info                      : Blu-ray Video
File size                        : 121 MiB
Duration                         : 37s 751ms
Overall bit rate                 : 26.8 Mbps
Maximum Overall bit rate         : 32.1 Mbps

Adjusted setting - 24Mbps:

File size                        : 117 MiB
Duration                         : 37s 756ms
Overall bit rate                 : 26.0 Mbps
Maximum Overall bit rate         : 30.9 Mbps

Adjusted setting - 18Mbps:

File size                        : 90.8 MiB
Duration                         : 37s 837ms
Overall bit rate                 : 20.1 Mbps
Maximum Overall bit rate         : 23.9 Mbps

And it is impossible for me to detect any difference in the output quality.

The filesize goes up sligthly with the 18Mbps setting (compared to source file) - but the total filesize compared to the 40Mbps is 25% reduced (91mb compared to 121mb).

In the "Picture type" setting I have used "BDMV(AVC)" - the other option is "BDMV(Mpeg2)" - dont know if that matters for the quality ??

My conclusion now is that with the current recorder I have - it does not make any sense to use "Best quality" - my filesize goes up - and I guess more processing is needed.

Am I right ?

thanks 

 

 

 

Cee5:

My conclusion now is that with the current recorder I have - it does not make any sense to use "Best quality" - my filesize goes up - and I guess more processing is needed.

Am I right ?

Yes, you are right. The advantages in terms of quality are minuscule. The disadvantage is large files size. I'd say (without testing) that the time to create the file would be about the same.

However, we sometimes see people come to this forum who are totally obsessive about "best quality". My answer was based on the possibility that you were one of those .

The mpeg-2 codec is not as efficient as the AVC codec, but is easier to play back. So for a given bitrate the mpeg-2 will be slightly lower in quality.

Just redid an existing 1hour project with 18mbps and compared to the 40mbps I got a reduction in the filezize from 7,8gb to 5,8gb 

If I cannot see much difference - I think I will go for that on future projects.

thanks for your valuable input.

Another advantage of a lower bitrate is that the disc can be read quicker - leading to less skipping if your discs have lots of errors. (All discs have errors, but they generally get corrected by the error correction)

I have stopped burning disks :)

Have an old Popcorn Hour box I use for streaming - but I dont use it so much any more. 

I use the BD fileset as input to Handbrake - and generate  a .m4v file - this way the resulting videofile contains Chapterinfo (Pinnacle cannot do any video file with chapters).

I then read the video over net to my ATV4 or iPad where I have Infuse installed (Infuse can see the chapter info).

Handbrake conversion also affects the bitrate. With the current settings I end up with a similar filesize and bitrate on the resulting .m4v files no matter what setting I have in Pinnacle (18 or 40 mbps)

I cannot see any difference in the resulting file (on my windows computer) - but I dont see much point in having Pinnacle "upscale" and then Handbrake "downscale" the bitrate. 

thanks again

Then what you are doing makes even more sense :-)