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add audio to a static image

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Shae Morgan
Shae Morgan on 18 Jun 2020
Commented: Shae Morgan on 19 Jun 2020
I have an audio signal and a picture. I'm trying to output a video of the static image for the duration of the audio that's playing. I'm woefully unskilled with the computer vision toolbox (but I have it). Could someone help me with this seemingly simply task?
videoFWriter = vision.VideoFileWriter('newvideo.avi','AudioInputPort',true);
videoFrame = im;
The output is a video file, but when I try to listen to the audio of it, it's been resampled and all sorts of crazy. Help!

Accepted Answer

Pranjal Kaura
Pranjal Kaura on 19 Jun 2020
The problem with your code seems to be that you’re not setting the frames per second parameter. If you don’t set it, the model assumes the FPS to be 30(default). Now when you add audio using the step command, its rushed/played quickly, to finish within the time frame of numFrames/FPS.
Here’s my solution. Hope this helps.
[data, freq] = audioread('pathtoAudioFile');
img = imread('pathtoImage');
audioLength = length(data)/freq;%duration of audio file
writerObj = vision.VideoFileWriter('newvideo.avi', 'AudioInputPort',true, 'FrameRate', 1);%Setting FPS to 1. Now we need to add atleast
%audioLength number of frames
for i = 1:audioLength
parsedAudio = data((i-1)*length(data)/audioLength + 1:i*length(data)/audioLength);%parsing the audio into equally sized pieces(play for 1 sec)
% that can be added with each img frame
step(writerObj, img, parsedAudio);
Shae Morgan
Shae Morgan on 19 Jun 2020
Thank you! that helps a ton.

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