Making an Animated Image Sequence

I want to make an animated sequence containing more than 500 png textures each compressed to 256x512. I used the method suggested in this post Unity: Animated texture from image sequence - Part 2 | 41 Post. But my question is whether this method is suitable to make animated image sequences on mobiles like android and iOS. When i tried this for android by loading all 600 png from the Resources folder i noticed a severe lag between frames and it didnt sync with the audio. This has also been specified in the post but the suggestion is to use movie texture which is not supported on iOS and Android. The first method suggests to use arrays but this can be a problem if I have image sequences with more than 500 frames. My main concern is how to make an animated sequence on mobiles

this is an animated texture script:

var frames : Texture2D[]; var framesPerSecond = 10.0;

 function Update () {
     var index : int = Time.time * framesPerSecond;
     index = index % frames.Length;
     renderer.material.mainTexture = frames[index];
 }

you input frame by frame so it may take a while

hope this helps