Blackmagic Forum

Hi everyone,

I downloaded two videos of a Facebook live stream (that are saved in Facebook) from an event I hosted. Using three online download and converting service websites I received the mp4 files from these three sources.

All mp4 files show the same problem: They have sound in Facebook and within the VLC audio player and the windows media player, but not within DaVinci Resolve, and not in a different video editing program I tested (Magix video deluxe).
In the timeline the audio track shows no signal vizualization at all.
All other mp4 files I tried (from different sources like YouTube, television media libraries or own camera recordings) work properly with sound. It's just the mp4 files that came from Facebook which have no sound only in video editing programs.

I already downloaded the k-lite_codec_pack_1465_basic.exe and installed it (with a restart of the computer), but that didn't help.

I changed the sound card settings for the speakers from 24 bit to 16 bit 44.100 Hz, with no difference.


Does anyone have an idea what might help to get the sound within DaVinci Resolve?




Under "DaVinci Resolve - Preferences - Video and Audio I/O" the settings are:
For capture and playback use: none (default setting)
For Resolve Live use: none (default)
Release video I/O hardware when not in focus: not enabled
Enable Fairlight Audio Accelerator: not enabled
Speaker Setup: Use System Setting
Device: Speakers (Realtek High Definition Audio)
Monitor Set Format: Stereo

I'm using DaVinci Resolve 15.2.2.007 with Windows 10 Home Version 1803 Build 17134.523.

Hardware: PC with Intel Core i7-8550U 64 Bit CPU 1,8GHz, 16 GB RAM

The analysis of the file by MediaInfo says:

Complete name : C:\Users\jgast\Downloads\parteitag1.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 499 MiB
Duration : 3 h 1 min
Overall bit rate mode : variabel
Overall bit rate : 383 kb/s
Writing application : Lavf56.40.101

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3
Format settings : CABAC / 3 Ref Frames
Format settings, CABAC : Ja
Format settings, RefFrames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 3 h 1 min
Bit rate : 312 kb/s
Width : 640 Pixel
Height : 360 Pixel
Display aspect ratio : 16:9
Frame rate mode : variabel
Frame rate : 29,970 (29970/1000) FPS
Minimum frame rate : 0,139 FPS
Maximum frame rate : 31,250 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : progressiv
Bits/(Pixel*Frame) : 0.045
Stream size : 406 MiB (81%)
Writing library : x264 core 148
Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=2 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=0 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=0 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=23.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=501 / vbv_bufsize=1000 / crf_max=39.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
Codec configuration box : avcC

Audio
ID : 2
Format : AAC LC SBR
Format/Info : Advanced Audio Codec Low Complexity with Spectral Band Replication
Commercial name : HE-AAC
Format settings : NBC
Codec ID : mp4a-40-5
Duration : 3 h 1 min
Bit rate mode : variable
Bit rate : 64,0 kb/s
Maximum bit rate : 127 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48,0 kHz
Frame rate : 23,438 FPS (2048 SPF)
Stream size : 83,3 MiB (17%)
Default : yes
Alternate group : 1


Thanks a lot in advance,

Joerg Gastmann, Cologne, Germany

Remember, MP4 is just a container. What is inside can vary. The answer to your problem is in the Mediainfo list. Frame Rate Mode; Variable. Resolve and other NLEs need Constant frame rate video to work with.
You will need to transcode them to a constant frame rate using something like Handbrake or Mpeg Streamclip.

Charles Bennett wrote:Remember, MP4 is just a container. What is inside can vary. The answer to your problem is in the Mediainfo list. Frame Rate Mode; Variable. Resolve and other NLEs need Constant frame rate video to work with.
You will need to transcode them to a constant frame rate using something like Handbrake or Mpeg Streamclip.

Untrue, as most NLEs have been updated specifically to work with this type of media: Premiere Pro, Final Cut Pro X, VEGAS Pro, Edius Pro, Lightworks, Video Pro X, etc. all work out of the box with this type of media. It isn't a problem.

I'm sure there are a few that don't work well with VFR. Resolve is one. Not sure about Avid.

With Resolve, you need to create Optimized Media. I don't generally recommend Handbrake, because the video usually ends up looking worse after you use it to transcode. Don't use MPEG Streamclip, so cannot speak of it.

If the audio isn't playing, the issue is more likely the Audio Codec used in the video file.

VFR problems usually manifest in awful playback performance, black video frames while the audio plays fine, or "Media Offline" for the video file in the media pool...

Charles Bennett wrote:Remember, MP4 is just a container. What is inside can vary. The answer to your problem is in the Mediainfo list. Frame Rate Mode; Variable. Resolve and other NLEs need Constant frame rate video to work with.
You will need to transcode them to a constant frame rate using something like Handbrake or Mpeg Streamclip.

Thank you very much for your help and your commendable support, Charles. Impressive know-how! Your advice solved the problem!
For those who run into the same problem of videos without sound within DaVinci Resolve or other NLEs (but with sound in VLC player, windows media player, etc): Download Handbrake (handbrake.fr/downloads.php) and follow the instructions of the YouTube video "How To Convert Variable Framerate Video To Constant (Audio Desync Fix)" by "Turbulent Limo" (youtube.com/watch?v=Hp2wiEUhV08). Set "Constant Framerate" in the video tab.

I don't think it is the variable framerate that cause the problem. I tried to "convert" the video using Handbrake with variable and constant frame rate setting, both of the output video work in Resolve.
It means for now (until BM fix it), you guys just need to let the Facebook video goes through Handbrake (or Premiere, export same as source) and the problem is solved.

I had a similar problem importing MP4 files to Resolve where the sound was not being imported. I found that the solution was to look at the import file attributes and make sure that 2 stereo tracks were specified.

I have a SOLUTION!!!!!!!!!!!

I can't tell you how much time I have spent trying every software product and combination of codecs to make MTS be an MP4 with actual audio. Finally, one worked:

Try this:

D:\Video\ffmpeg\bin\ffmpeg -i 00040.MTS -vcodec mpeg4 -b:v 15M -acodec ac3_fixed -b:a 192k 00040.mp4

This is the magic bit:

-acodec ac3_fixed

Ironically, this will not play audio in VCL, but it works in Resolve... and thats all anyone cares about if they are reading this.

Hi Javakinetic, thank you for sharing, but may I know specifically where to place the syntax you have shared? I have tried converting the file in HandBrake, but I still have the same no audio detected in Resolve.

Thank you in advance.

javakinetic wrote:I have a SOLUTION!!!!!!!!!!!

I can't tell you how much time I have spent trying every software product and combination of codecs to make MTS be an MP4 with actual audio. Finally, one worked:

Try this:

D:\Video\ffmpeg\bin\ffmpeg -i 00040.MTS -vcodec mpeg4 -b:v 15M -acodec ac3_fixed -b:a 192k 00040.mp4

This is the magic bit:

-acodec ac3_fixed

Ironically, this will not play audio in VCL, but it works in Resolve... and thats all anyone cares about if they are reading this.

I have tried the Handbrake solutuon but it still doesn't work.
@Javakinetic can you explain a little more what you did. I'm not sure what to do, to try your fix.

I encountered the same situation today, where I downloaded some "Like subscribe" video endings from a YouTube channel giving them away for free. The video played in VLC with sound but when imported into Studio 17 Beta 7 there was no sound in the clip. I tried every suggested method to convert the file with Handbrake, VLC and ffmpeg and nothing worked. What DID eventually work was I imported the clip Into Resolve Free 15 on my Macbook, and then rendered it from there and voila it was fixed.

One thing you can always try is to extract the audio from the video file, convert it to a WAV, and import it separately.

Using ffmpeg that would be:

Code: Select all

ffmpeg -i <your troublesome video file>.mp4 -vn -acodec pcm_s16le audio_only.wav

-i : input
-vn : disable video
-acodec : audio codec to be used, 16 bit PCM in this case, for a WAV file

A solution is to encode the video with h264 codec and pcm audio into a .mov file instead of .mp4. Then it works.

If you use ffmpeg then:

ffmpeg -i inputfile.mp4 -acodec pcm_s16le -vcodec copy outfile.mov

The "-vcodec copy" simply means that the video codec in the input file will be copied to the outfile, so this goes fast since there is no re-encoding of video done, and you don't have to export the audio separately and all that.

That's the correct solution. Covert audio to wav, copy video and remux.

glcohen wrote:I had a similar problem importing MP4 files to Resolve where the sound was not being imported. I found that the solution was to look at the import file attributes and make sure that 2 stereo tracks were specified.

This solution worked for me, and I wanted to provide a few more details for others. I had a downloaded Youtube clip that was playing audio in the preview window in the Media Pool, but not importing the audio into my timeline.

In the media pool, I right-clicked on the offending clip, and selected "Clip Attributes." I think messed around with the settings under the "Audio" tab. The clip had one Mono channel listed, but I added another one both coming from the same source channel ("Embedded Channel 1"). This fixed the issue for me.

This is a problem I experience currently when doing screen saves using Icecream Screen Recorder.

It produces .MP4 video clips that can be played by VLC, Media Player, etc. without any issues.

But in DR17, I have no audio.

To get around this, I use my VideoProc Coverter application to convert the MP4 to MP4.

The AUDIO information before converting looks like this:

Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Mode : Joint stereo
Mode extension : MS Stereo
Codec ID : 6B
Duration : 10 min 24 s
Duration_LastFrame : -1 ms
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Sampling rate : 44.1 kHz
Compression mode : Lossy
Stream size : 14.3 MiB (7%)
Default : Yes
Alternate group : 1


The AUDIO information AFTER converting looks like this:

Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 10 min 24 s
Duration_LastFrame : -19 ms
Bit rate mode : Constant
Bit rate : 128 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 spf)
Compression mode : Lossy
Stream size : 9.55 MiB (5%)
Default : Yes
Alternate group : 1

I'm no video/audio expert and don't know much about this stuff. What I can notice from this is that by converting I've gone from MPEG Audio Version 1 to AAC. It would seem to me that DR17 does not like MPEG Audio v1. I don't know.

But for now that's the solution I have and it works for me, although I wish I didn't have to go this extra step.

DR is possibly having issues because your MP4 file has MP3 audio in it instead of AAC, which is outside of the official format specifications.

Try recording using OBS instead, it will give you more control over the format of your screen recording files (including AAC audio).

Rixcandoit wrote:This is a problem I experience currently when doing screen saves using Icecream Screen Recorder.

It produces .MP4 video clips that can be played by VLC, Media Player, etc. without any issues.

But in DR17, I have no audio.

To get around this, I use my VideoProc Coverter application to convert the MP4 to MP4.

The AUDIO information before converting looks like this:

Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Mode : Joint stereo
Mode extension : MS Stereo
Codec ID : 6B
Duration : 10 min 24 s
Duration_LastFrame : -1 ms
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Sampling rate : 44.1 kHz
Compression mode : Lossy
Stream size : 14.3 MiB (7%)
Default : Yes
Alternate group : 1


The AUDIO information AFTER converting looks like this:

Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 10 min 24 s
Duration_LastFrame : -19 ms
Bit rate mode : Constant
Bit rate : 128 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 spf)
Compression mode : Lossy
Stream size : 9.55 MiB (5%)
Default : Yes
Alternate group : 1

I'm no video/audio expert and don't know much about this stuff. What I can notice from this is that by converting I've gone from MPEG Audio Version 1 to AAC. It would seem to me that DR17 does not like MPEG Audio v1. I don't know.

But for now that's the solution I have and it works for me, although I wish I didn't have to go this extra step.

Yes Resolve doesn't like mp3 in mp4. No idea why it makes such a fuss about this and that codec working only from this and that container. Many threads about the limitation.

In particular the differences between MKV and Webm are strange, as WEBM is a valid MKV file by definition.