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I have faced a strange issue of syncing video action with audio. I am working in a Project. The entire project is of 4787 frames (Start frame 2154 and End frame 7150). There are numbers of audio files and connected lip synch & actions were prepared. Before putting the file in image sequence rendering, everything was checked (including fps) and all Audio- Video syncing were fine. However, after finishing the image rendering of 4787 nos. of images, and also finishing final video rendering, it is found that the audio and video are not synced. While examining it is found that every audio files in VSE are scaled down from their respective start frame. The Screenshot may please be seen. In the screenshot, previously, the audio file ‘X’ and NLA strip ‘Y’ were perfect paired. However, it can be seen now that the audio file ‘X’ start frame is 2157 and the end frame is 2323 but the lip sync audio strip ‘Y’ start frame is 2157 and the end frame is 2363. There are total 18 nos. of audio files and NLA strips. For each of the audio file and NLA strips start frame is same but somehow audio files are scaled down. Because Camera marker ‘Z’ and NLA strips ‘Y’ are matched, only the audio file ‘X’ is somehow scaled down for each NLA action. If I replace the audio file ‘X’ from the original audio file saved in my PC, the length of audio file is unchanged. Screensh

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Maybe a 44.1 vs 48 Khz Sample rate conflict?

enter image description here

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  • $\begingroup$ Would you please describe a little for my understanding. $\endgroup$
    – Tanmoy Roy
    Oct 30, 2023 at 9:55
  • $\begingroup$ 44.1 means that sounds get sampled 44100 times per second. If your audio has been recorded at 44.1 kHz, and then it gets read at 48 kHz, as the number of samples remains the same, the audio will get shorter (and shifted up in tonality). Many softwares recognize the sample rate and change accordingly, or give you an alert, but Blender doesn't. $\endgroup$ Oct 30, 2023 at 12:17
  • $\begingroup$ 44.100 is standard for CD production, 48 in film industry, 96 and 192 for hi end productions. The quality difference between them is barely noticeable (unless you do heavy processing). $\endgroup$ Oct 30, 2023 at 12:22
  • $\begingroup$ Thank you very much for your detailed explanation. I have examined that my Blender default settings was 48kHz and the audio files were of 44.1kHz. However, when I transfer my audio file of 44.1kHz to 48kHz in Audacity, duration of both the audios (i.e. 44.1 kHz and 48 kHz) are same only audio quality changes a little. I am providing both the audios as Google drive links. Audios are in Bengali language but regarding technicalities there would be no issue. drive.google.com/drive/folders/… $\endgroup$
    – Tanmoy Roy
    Oct 30, 2023 at 23:57

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