@sjmackinder

Hi.

I've just noticed your other replies.

On the faulty file the audio frame rate has changed and you have exported at 25fps rather than the 50 fps of the original. Neither is a good idea to try. Whether changing the frame rate of the export has caused the frame rate of the audio to change so it eventually drifts or not I can't say but it could be a good bet.

Ray.

what makes this worse is that I have spent 2 days editing multiple camera footage from an event at Windsor Castle so that the Queen can watch a DVD of this to then be stored in the tower for long term records. I just hope when I come to burn the DVD ProX14 does not do the same thing - create the DVD with out of sync issues as this would be a disaster

@sjmackinder

Hi Simon

There is some missing information - the first MediaInfo analysis is not what you have on the timeline in the image above. AFAICS the timeline has 2 different video file formats mp4 and .mts video files it is the analysis from these source files I asked for.

I presume the first MediaInfo analysis is from the first export of that project and that it plays OK, is this correct?

BTW in your profile signature the graphics stated is an RTX 3600, do you mean RTX 3060?

John EB

yes that is correct the second report is the compressed file that does not play correctly. I changed my profile when I upgraded my graphics drivers having spotted this mistake 3600/3060

I have now found that if I export the file using vpx14 as mpg and not mp4 there is no issue at all

@sjmackinder

Hi Simon.

As a matter of interest, could you please give us the media info for the working exported file?

Ray.

yes of course, no problem.....

General
Complete name                            : H:\Event Videos\Windsor Castle 27th July 2022\2022-08-02.mpg
Format                                   : MPEG-PS
File size                                : 118 MiB
Duration                                 : 2 min 35 s
Overall bit rate mode                    : Variable
Overall bit rate                         : 6 339 kb/s

Video
ID                                       : 224 (0xE0)
Format                                   : MPEG Video
Format version                           : Version 2
Format profile                           : Main@Main
Format settings                          : BVOP
Format settings, BVOP                    : Yes
Format settings, Matrix                  : Default
Format settings, GOP                     : M=3, N=12
Format settings, picture structure       : Frame
Duration                                 : 2 min 35 s
Bit rate mode                            : Variable
Bit rate                                 : 5 989 kb/s
Maximum bit rate                         : 9 500 kb/s
Width                                    : 720 pixels
Height                                   : 576 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 25.000 FPS
Standard                                 : PAL
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan order                               : Bottom Field First
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 0.578
Time code of first frame                 : 00:00:00:00
Time code source                         : Group of pictures header
GOP, Open/Closed                         : Closed
Stream size                              : 111 MiB (94%)
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709

Audio
ID                                       : 192 (0xC0)
Format                                   : MPEG Audio
Format version                           : Version 1
Format profile                           : Layer 2
Duration                                 : 2 min 35 s
Bit rate mode                            : Constant
Bit rate                                 : 224 kb/s
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 kHz
Frame rate                               : 41.667 FPS (1152 SPF)
Compression mode                         : Lossy
Stream size                              : 4.15 MiB (4%)

Menu
Format                                   : DVD-Video

For direct comparison here is a mp4 that does not play correctly

General
Complete name                            : H:\Event Videos\Windsor Castle 27th July 2022\Test.mp4
Format                                   : MPEG-4
Format profile                           : Base Media
Codec ID                                 : isom (isom/avc1)
File size                                : 41.2 MiB
Duration                                 : 2 min 6 s
Overall bit rate mode                    : Variable
Overall bit rate                         : 2 731 kb/s
Encoded date                             : UTC 2022-08-02 08:22:08
Tagged date                              : UTC 2022-08-02 08:22:08

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L3
Format settings                          : CABAC / 2 Ref Frames
Format settings, CABAC                   : Yes
Format settings, Reference frames        : 2 frames
Format settings, GOP                     : M=2, N=25
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 2 min 6 s
Bit rate mode                            : Variable
Bit rate                                 : 2 595 kb/s
Maximum bit rate                         : 3 599 kb/s
Width                                    : 768 pixels
Height                                   : 432 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 25.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.313
Stream size                              : 39.2 MiB (95%)
Language                                 : English
Encoded date                             : UTC 2022-08-02 08:22:08
Tagged date                              : UTC 2022-08-02 08:22:08
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                                 : 2 min 6 s
Bit rate mode                            : Variable
Bit rate                                 : 132 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                              : 1.99 MiB (5%)
Language                                 : English
Encoded date                             : UTC 2022-08-02 08:22:08
Tagged date                              : UTC 2022-08-02 08:22:08

@sjmackinder

Thank you.

There are two striking differences just at a quick glance.

The frame sizes are different but more importantly the file that is wrong has the wrong audio sample rate as well as a lower frame rate.

Ray.

@sjmackinder

Worth a try: in the Advanced section of the MPEG-4 export screen, set the audio to 48,000khz. You've currently got 44.1.

If that doesn't work, all is not lost, try exporting out as "Video as Magix Video". You'll get a fairly large MXV file. Load that back into a new project and try exporting at your 768x432 MPEG-4.

@CubeAce

Ray, do we have any control over the audio frame rate? I've never looked at it.

@sjmackinder

You could also try a more "standard" 720x576 16:9 for export.

Clearly though there is something astray with VPX 14 if 7 does the job.

OK tried the 48Khz option no difference still way out of sync. Tried the MXV export then reloaded and exported as mp4 this is fine although the mxv file will be huge running at around 0.75Gb/min. Tried a standard at 720x576 still way out.

@AAProds

Hi Alwyn

My names not 'Ray' 😀

. . . . do we have any control over the audio frame rate? . . . .

Yes - change the Sample rate.

Audio samples are allocated into 'audio frames' which are independent of the video frame rate

The audio framerate it is the Sample rate divided the Samples per frame (SPF).

AAC allocates 1024 samples per frame, so for 48000 samples/s the audio framerate is 48000/1024 = 46.875 FPS

AC 3 allocates 1536 SPF

HTH

John EB

Is this because I am doing a double mp4 export ie the original edit has many different files etc then exported to mp4 at around 6.5GB and then when importing this file and exporting again to a lower res the sync issue happens...?

Although using VPX7 it handles the 6.5GB mp4 perfectly albeit a bit slower

@johnebaker

John, I was responding to Ray's comment:

 the file that is wrong has the wrong audio sample rate as well as a lower frame rate.

So we don't actually have any control (directly) over the audio frame rate. Set the sampling rate and the rest will fall in to place.

@sjmackinder

Is this because I am doing a double mp4 export ie the original edit has many different files etc then exported to mp4 at around 6.5GB and then when importing this file and exporting again to a lower res the sync issue happens...?

No, it shouldn't make any difference. An exported MPEG-4 is an exported MPEG-4. All the warts and ziggles of your source files are vapourised into AVC format video and AAC audio when exported. VPX 14 should be able to re-encode that something smaller.

@AAProds

Hi

. . . . So we don't actually have any control (directly) over the audio frame rate. Set the sampling rate and the rest will fall in to place. . . . .

That is correct, we have no control over the SPF setting - this is 'standardised' for the audio format and number of channels

John EB

@AAProds

Hi Al.

Sorry for the late reply as I've been out.

Wrong was probably the incorrect word to use. I should have said different to the source file.

That sample rate difference as you saw, altered the frame rate. That is normal as far as I know as per John's explanation but I'm worried if this is similar to MEP / VPX not coping with variable frame rates as well as the programs once did.

Whether something is going wrong because of this or not I don't know.

Maybe it requires a ticket just to let Magix know the situation. I don't think this should occur.

I never mix sample rates in my projects or frame rates normally. I have no idea if this would be considered a bug or not.

Gid's reply in reply in another post where he has stated his machine is not having problems with variable frame rates makes me wonder if to get trouble free editing we have to up our machine specs quite a bit from the minimum quoted on the specs pages.

Ray.

It is certainly not something I am doing intentionally as I would not even know how to do this. It is very worrying that their latest VPX software seems less capable in this area than a much earlier release

@CubeAce, @sjmackinder

Hi Ray, Simon

. . . . Gid's reply in reply in another post where he has stated his machine is not having problems with variable frame rates . . . .

We do not know that the mp4 and mts source video files Simon is using are VFR, and the MediaInfo data from the exports are all CFR.

There is something odd though - the SD.mp4 is h.264/AVC encoded with a 44.1 kHz - the question is how did the audio sample rate become 44.1kHz ?

VPX will not let you export h.264/AVC with 44.1kHz audio, even if you set the project to 44.1kHz - nor can the sample rate be changed in the export presets.

I have not had any issues mixing different audio sample rates, most of the music is 44.1kHz sample rate and in some videos I have made the video is synced to the music.

John EB