Iphone screen capture video audio/video not sync

Greg-Carter wrote on 2/16/2019, 11:06 AM

I have a video I created using my Iphone (Iphone 5s, IOS 11.2.6) using the built in screen capture feature. I also captured the microphone audio. After doing a bunch of editing on this file I noticed that the captured audio was not in sync with the video. However if I played the video using Windows Media Player the audio/video play back in sync. I then created a new project and added just the one video file, and attempted play it back, again the audio was not in sync with the video. I tried rendering it, and it render out - out of sync. I don't mean just a little out of sync, it's way off. Is this because it's variable bit rate? Using version 15 build 157.

General
Complete name : D:\media\video\land rover lr3\coldbrakelightswitch\AUZB4975.MP4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (mp41/mp42/isom)
File size : 11.1 MiB
Duration : 1 min 50 s
Overall bit rate : 843 kb/s
Encoded date : UTC 2019-02-15 15:01:56
Tagged date : UTC 2019-02-15 15:03:48

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings : CABAC / 2 Ref Frames
Format settings, CABAC : Yes
Format settings, RefFrames : 2 frames
Format settings, GOP : M=1, N=30
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1 min 50 s
Bit rate : 732 kb/s
Width : 1 080 pixels
Height : 1 920 pixels
Display aspect ratio : 0.563
Frame rate mode : Variable
Frame rate : 18.020 FPS
Minimum frame rate : 0.186 FPS
Maximum frame rate : 66.667 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.020
Stream size : 9.67 MiB (87%)
Title : Core Media Video
Encoded date : UTC 2019-02-15 15:01:56
Tagged date : UTC 2019-02-15 15:03:48
Color range : Full
Codec configuration box : avcC

Audio #1
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 min 50 s
Source duration : 1 min 50 s
Bit rate mode : Constant
Bit rate : 2 067 b/s
Nominal bit rate : 128 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 : 28.0 KiB (0%)
Source stream size : 28.0 KiB (0%)
Title : Core Media Audio
Encoded date : UTC 2019-02-15 15:01:57
Tagged date : UTC 2019-02-15 15:03:48

Audio #2
ID : 3
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 min 50 s
Source duration : 1 min 50 s
Bit rate mode : Constant
Bit rate : 104 kb/s
Nominal bit rate : 128 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 : 1.38 MiB (12%)
Source stream size : 1.38 MiB (12%)
Title : Core Media Audio
Encoded date : UTC 2019-02-15 15:01:57
Tagged date : UTC 2019-02-15 15:03:48

Comments

Greg-Carter wrote on 2/16/2019, 11:20 AM

OK I just used Handbrake to convert the file to constant frame rate and it seems to be behaving correctly inside Movie Studio. So is this a bug or a known limitation?

Thanks

General
Complete name : D:\media\video\land rover lr3\coldbrakelightswitch\converted\first_constant.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (isom/iso2/avc1/mp41)
File size : 5.65 MiB
Duration : 1 min 50 s
Overall bit rate mode : Variable
Overall bit rate : 427 kb/s
Encoded date : UTC 2019-02-16 17:10:13
Tagged date : UTC 2019-02-16 17:10:13
Writing application : HandBrake 1.1.1 2018061800

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L4
Format settings : CABAC / 4 Ref Frames
Format settings, CABAC : Yes
Format settings, RefFrames : 4 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1 min 50 s
Bit rate : 259 kb/s
Width : 1 080 pixels
Height : 1 080 pixels
Display aspect ratio : 0.563
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) : 0.007
Stream size : 3.42 MiB (61%)
Writing library : x264 core 155 r2901 7d0ff22
Encoding settings : cabac=1 / ref=2 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=6 / 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=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=1 / keyint=300 / keyint_min=30 / scenecut=40 / intra_refresh=0 / rc_lookahead=30 / rc=crf / mbtree=1 / crf=22.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=20000 / vbv_bufsize=25000 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
Encoded date : UTC 2019-02-16 17:10:13
Tagged date : UTC 2019-02-16 17:10:13
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 min 50 s
Bit rate mode : Variable
Bit rate : 160 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 : 2.12 MiB (38%)
Title : Stereo / Stereo
Default : Yes
Alternate group : 1
Encoded date : UTC 2019-02-16 17:10:13
Tagged date : UTC 2019-02-16 17:10:13

j-v wrote on 2/16/2019, 11:43 AM

Seems logic to me . Your first mediainfo tells us that the bit rate is variable of the 18fps it detects on your file. Sadly you did not tell us what VMS 15 is seeing it in the fileproperties.
Converting for smartphonefiles is mostly good but changing if from 18 to 30 CFR is a big step and than it is logic that VMS detect it as a 30 fps file without problems on the timeline as result. No limitation or bug.

Greg-Carter wrote on 2/16/2019, 11:56 AM

Sadly you did not tell us what VMS 15 is seeing it in the fileproperties.
No limitation or bug.

It's one or the other, not neither. The file did not even play back correctly from within Movie Studio.

I don't know of any way to gather the file properties from within Movie Studio other than screen capture, so here it is:

It reports the frame rate as 18.020fps.

j-v wrote on 2/16/2019, 12:39 PM

You can see it in your screen number 1 and 2 in the General part of the properties at the end.

But VMS sees it as 18fps as you showed and your projectproperties are?????

Greg-Carter wrote on 2/16/2019, 3:28 PM

Hi,

It was set to match the main video file I was using (selected at time of project creation, where you have the option to select a file to match settings). Which was:

Custom (1280x720, 29.982 fps). FWIW that was another file produced by an iphone 5s.

In the past I haven't had problems mixing files with different frame rates, at least that I can remember. I know I've used 1080p 24fps from my DSLR, with various iphone 30/60 up to 4k and haven't run into this problem. It wasn't until I tried with this 18fps screen capture that I ran into it.

Thanks

Greg.

Greg-Carter wrote on 2/16/2019, 3:35 PM

As a test I right clicked the media file and selected "Match project video settings". This resulted in the test project frame rate matching this video file. Playback was still not synced.

j-v wrote on 2/16/2019, 3:38 PM

Now you know the possible reason, what is happening if your project has only that files and your projectsettings are according this?
If it again gives you the troubles than it is better to convert it with handbrake to a constant framerate you use as projectsettings.

VMS is a video editor and not an editor for smartphonefiles alone.

Greg-Carter wrote on 2/16/2019, 4:02 PM

Hello,

That test above was with only one file in the project.

I have now done another test using an iphone 8plus screen capture with audio. It again can not play back synced. You can see here that it's not even displayed correctly in the timeline, it cuts off the audio track.

A test project is here:

http://www.carter-engineering.com/files/test_iphone8plus_screencap.zip

The media file plays back fine with Windows Media Player.

While Movie Studio may not be a "smart phone editor" there's no reason it should not be able to handle this file gracefully.

First thanks for your help, it's not clear to me from your user name if you work for Vegas. If you do please submit a bug report for this.

vkmast wrote on 2/16/2019, 5:38 PM

The Magix employees can be recognized from this hexagon graphic attached to their avatar . The developers keep an eye on these forums and may post and comment here from time to time. The other forum contributors, including the moderators, are peer users not working for Magix/Vegas. I'd think your issue is "a known limitation" (see also here), but you can make a Support request yourself explaining the issue.