ahmedtanjim This is because not all editions are available at the same bitrate of 128. The edition itself tells you what bitrate it is available at - for instance https://api.alquran.cloud/v1/ayah/1/ar.abdulbasitmurattal shows that ar.abulbasitmurattal is available at 192 and 64.
If you want to see the bitrate for all editions, this txt file shoudl help: https://github.com/islamic-network/cdn/blob/master/info/cdn.txt.
