Resolve18 Render Settings - Advice requested

How do I assure that I always render videos that are the same quality as the original but are not massively larger?

Would appreciate as much detail as you have the patience to provide.


Here is a comparative example: The first file played approx 40 mins. I cut out half of it and ended up with a file that is more than twice the size.

The original was downloaded and rendered with a software called VideoDownloadHelper:

General
Complete name : E:\My Videos\rendered by VDHelper.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 639 MiB
Duration : 40 min 33 s
Overall bit rate mode : Variable
Overall bit rate : 2 203 kb/s
Movie name : Tucker Carlson Tonight Season 2023, Episode 56, Monday, Marc
Performer : WinX HD Video Converter Deluxe
Writing application : Lavf58.29.100

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L4
Format settings : CABAC / 3 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 40 min 33 s
Bit rate mode : Variable
Bit rate : 2 068 kb/s
Maximum bit rate : 6 000 kb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 30.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.033
Stream size : 600 MiB (94%)
Codec configuration box : avcC

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 40 min 33 s
Bit rate mode : Constant
Bit rate : 129 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 37.4 MiB (6%)
Default : Yes
Alternate group : 1

This is the Resolve 18 render using Custom defaults with the following 3 changes:
Format: MP4, Codec: H.265, Encoder: NVIDIA

General
Complete name : E:\My Videos\Rendered by Resolve18.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/mp41)
File size : 1.48 GiB
Duration : 22 min 9 s
Overall bit rate : 9 575 kb/s
Encoded date : UTC 2023-03-21 22:33:11
Tagged date : UTC 2023-03-21 22:33:11
Writing application : Blackmagic Design DaVinci Resolve Studio

Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main@L4@Main
Codec ID : hvc1
Codec ID/Info : High Efficiency Video Coding
Duration : 22 min 9 s
Bit rate : 9 378 kb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 30.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.151
Stream size : 1.45 GiB (98%)
Encoded date : UTC 2023-03-21 22:33:11
Tagged date : UTC 2023-03-21 22:33:11
Color range : Limited
Color primaries : BT.709
Matrix coefficients : BT.709
Gamma : 2.400
Codec configuration box : hvcC

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 22 min 9 s
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 30.4 MiB (2%)
Default : Yes
Alternate group : 1
Encoded date : UTC 2023-03-21 22:33:11
Tagged date : UTC 2023-03-21 22:33:11

Other
ID : 3
Type : Time code
Format : QuickTime TC
Duration : 22 min 9 s
Frame rate : 30.000 FPS
Time code of first frame : 01:00:00:00
Time code of last frame : 01:22:09:11
Time code, stripped : Yes
Language : English
Default : No
Encoded date : UTC 2023-03-21 22:33:11
Tagged date : UTC 2023-03-21 22:33:11

How do I assure that I always render videos that are the same quality as the original but are not massively larger?

When you're starting out with highly-compressed H.264 files, and then you're re-compressing them again in another format, you're going to lose quality and there's just no way to avoid it.

If file size is an issue, you could try limiting the bitrate on the Deliver page to some reasonable number like 30,000 or 25,000 or 20,000 and see which gives you the file size you need.

But "same quality as the original"... it's always going to be worse. The question is whether you can see the loss of quality or not, and that's a little unpredictable.

How do I assure that I always render videos that are the same quality as the original but are not massively larger?

You can't.

To ensure no quality loss, you need Uncompressed. And those files will be HUGE!

That said, I find the quality loss of the following settings to be pretty minimal. Give them a try. (Change the Resolution, Frame rate and Keyframes appropriately.)

SDR Deliver.png (63.97 KiB) Viewed 1671 times

You need to accept that any compression for video (other than very inefficient RLE) is lossy.
Even changing a single pixel will force codecs like H.264/265 into the next generation of compression. Codecs like Cineform, DNxHR or ProRes are much more robust and should be preferred if you need a master file for future changes and recompression.

Thanks to those who replied. I didn't see an option to reply to each individually. Did I miss something?

The one post is fine, Richard. We can all see it.

I probably asked the wrong question. It is not vital that I retain the same quality. I just want good quality. Here's were I'm confused. I often download news programs that result in files in the 1.5 gigabyte range. I use various software including a couple that capture the screen. Regardless of what those software are doing under the hood I always get good results. Here's the rub. After I edit out 40% of the content and add only simple transitions between cuts I end up with files that are between 2.5 and 3.5 gigabytes. I should have asked how can I produce files that are no larger than the originals without significant quality reduction. Compression is fine.

Resolve might not be the best tool for that task.

You might do better with software that has a Smart Render feature for H.264 media, where only the changed parts get rendered, and everything unchanged just gets copied.

What export codec are you using? H265 will give you good quality and small file sizes.

Also, what are the pixel dimensions of the original recording, and what are the pixel dimensions of your output ?

FWIW, here's what I do:

Always render to Resolve Master, wide open both video and audio. Huge file, yes, quick render time. I often delete this later on unless I have some partcular reason to retain for a while.

Then open that Master in (free) Handbreak. - here you can try varous presets, or try out some settings for various destinations etc. I find I get better and more consistent results here and depending on seetings, a far better match to the master. Usually a HQ H264 & 160bps audio MP4 does pretty well for most of my uses (eg, YouTube, Plex home server etc). Plus there's still always an option to render otherwise for a particular client or destination requirement.

Rather than recommendations for a 'one size fits all' scenario, Handbreak allows you to try out different options, tweak a little if necessary, and learn from that interaction.

Second that.