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  • Karl Buhl

    January 28, 2022 at 1:59 am in reply to: Sound disappeared

    Jean, the green fill of the clips indicates that DaVinci sees the files on your hard drive. Otherwise you would see the red missing media icon. So, the only thing that comes to my thought is that the files are corrupted. One test is to open the source files on the hard drive and see if they play outside of DVR. That would indicate if the source files are corrupted, or not.

    Assuming you have original copies of the audio clips, have you tried to delete them from the drive and folder location, and re-copying to the appropriate DVR folder and re-linking the files?

    Is your hard drive running directly off the motherboard, or is it on a USB drive or a network drive. Possible that it’s a cable problem or hard drive corruption.

    Possible, but not likely, that DVR is corrupted. You could try re-installing DVR.

    Sorry, that I’m guessing here, but those are my ideas for isolating the problem.

  • Hi Michael. Thanks for your suggestion.

    The audio clip was originally sampled at 44.1. I used Audacity to resample up to 48 (Audacity makes re-sampling very easy.) The problem continued with the up-sampled 48 kHz clip.

    I added a separate audio track for this new 48 kHz clip, used the audio waveforms to visually sync with the video, and ran a sample render. The audio rendered normal speed perfectly in sync with the audio. Very strange.

    Do you think the bit depth would impact this? I think the re-sampled clip was @ 32-bit variable instead of 24-bit.

    I’d like to eventually figure out the problem, but at this point I probably won’t spend the time to chase it.

    Thanks for your assistance.

    Cheers,

  • Karl Buhl

    September 7, 2021 at 1:06 am in reply to: KEYBOARD SHORTCUT TO ADVANCE COMPLETE FRAME?

    I believe Shift + right arrow advances 1-frame in DaVinci Resolve.

  • One final, follow-on question. The final AMD-rendered files are 40%-50% smaller than the same files rendered via the Intel i9.

    Why would the final AMD-rendered file size be so much smaller? Am I sacrificing video quality using the AMD Radeon RX 570 video card?

    Thank you,

    Karl

  • Hi Tom. Thank you for all of your suggestions. See my previous response to Paul—when I rendered through the AMD Radeon RX 570 card … problem solved.

    I will look at all of your suggested settings to determine if these variables change the outcome in any way.

    Thank you for digging in. Greatly appreciated.

    Karl

  • Paul—Thank you for your response—and for clearly explaining the codec compression issues. Your description of the issues makes perfect sense because, yes, each video frame changes.

    You provided me with several ‘ah-ha’ moments. The first of which was an assumption (bias) that the onboard Intel i9 would out-render the graphics card. My graphics card is an AMD Radeon RX 570. Not super high-end. But certainly adequate.

    Many of the options you suggested to try in DaVinci are only available when selecting the graphics card as the rendering engine. So my first test was to simply render through the Radeon card.

    That solved the problem. The test video played perfectly through the LG TV without changing any other settings.

    Uncertain why the i9 wasn’t up to the job. But thank you for your suggestions that led me to a solution. Greatly appreciated.

    Karl

  • After clearing this with COW’s managing editor, here are two links if anyone wants to dig in further:

    1. Link to my ~ 42-second test video. The first scene plays normally on the LG TV. When it gets to the fast-forward segment, then it fails (per the above descriptions). (Download link expires in 1-month.)

    https://karlbuhl.filemail.com/d/phutbtifquzyqlt

    2. Link to specifications for the LG OLED-77C1AUB.AUS:

    https://www.lg.com/us/tvs/lg-oled77c1aub-oled-4k-tv

    Thanks again to all those helping me analyze this.

  • Answers to questions & suggestions:

    1. Do any videos play on the LG TV.

    Yes. >MOST< of my 4K videos will play on the LG OLED-77C1AUB.AUS through an external SSD connected via USB. >ALL< of the fast-forward sequences fail at some point in the sequence. >SOME< of the normal-speed 4K video also fails during the normal course of playback (which, to me, suggests the TV processor is unable to process the bits coming in).

    It doesn’t make any difference if the source device (into the USB port) is a thumb drive or and external SSD.

    Also, I have tried different USB ports in the TV. No difference in performance.

    2. Do the videos play on your PC?

    Everything plays just fine on my Windows 10 PC—irrespective of whether the file is on an internal SSD or external SSD via USB. No problems. Smooth as butter.

    (I do not have another TV to test on.)

    3. Version of Resolve?

    Paid Studio version.

    4. Bit depth?

    Bit depth = 10

    5. Have you tried MOV?

    Yes. The MOV file crashes much worse than the MP4 files.

    I have tested several additional variations since my original post. (Everything below was rendered H.264 codec, 3840 x 2160 UHD—except the one Hi Res file as noted. All 29.97 frame rate.) Render speed in DaVinci = 10%.

    “Failed” means that the video and audio failed to play back smoothly. It stammered, stuttered, paused, and generally “choked” (my terminology for all of the above).

    1) MOV played back via thumb drive = fail.

    2) MOV PB via external SSD = fail.

    3) MP4 rendered “high” vs. “best” PB via thumb drive = fail.

    4) MP4 rendered “high” vs. “best” PB via external SSD = fail.5) MP4 rendered Hi Res 1920 x 1080 = still failed!

    5) MP4 restricted to 8,000 Kb/s = played back but severe pixelation (defeats purpose of 4K).

    6) MP4 restricted to 10,000 Kb/s = played back but severe pixelation (defeats purpose of 4K).

    I also attached the external SSD USB drive to my Surface Pro, and played the same video file on the SP via HDMI to the LG TV. The 42-second test clip appeared to play fine this way on the LG. Hmmm. Again points to the TV processor.

    However, I don’t understand why it would choke on the fast-forward rendered segments. Rendered video is rendered video. Would there be more data in the fast-forwarded segments? I’m not an engineer, so I don’t know the answer to this question. The fast-forwarded segments are where the video ALWAYS fails.

    Tom: If you (or anyone) wants to roll up your sleeves to test this, I can provide a link to download my ~ 42-second 4K test clip. You can test it on your PC, and then test it on your LG via a USB connection.

    (Creative Cow will not allow me to add the link here.)

    LG, working through a local repair business, is scheduled to send a new main board next week. I have a hard time believing that a new solid state board that passed LG’s QA went bad. However, the TV’s on-board processor does not appear to be up to the task. If that’s the case, the TV’s performance isn’t meeting it’s own specifications, which are available here:

    Thanks to everyone applying brain cycles to this. I appreciate your help.

    Karl

  • Jon: Thank you for your suggestion. I will test quality settings and report back.

  • Tom: Thank you for your suggestions. I will test these scenarios and report back.

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