How is the bandwidth attribute in the master m3u8 playlist determined?

Question

I have read from many sources that BANDWIDTH is a required attribute, supposedly to be an upper bound of the actual bitrate of the video, while also allowing for "container overhead."

#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,RESOLUTION=480x270,CODECS="avc1.42001e,mp4a.40.2",BANDWIDTH=663000
test110_600_.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,RESOLUTION=640x360,CODECS="avc1.4d001f,mp4a.40.2",BANDWIDTH=1088000
test110_1m.m3u8

How is this BANDWIDTH=663000 and BANDWIDTH=1088000 determined? Or rather, how should it be determined? Test runs with the Amazon Elastic Transcoder give seemingly wild results, especially when using videos of short duration; with Amazon's services I have created playlists where the bitrate of the video rose above the BANDWIDTH specified in the m3u8 file.

Answer 1

The bandwidth is overall bitrate of the movie (including transmission overhead).

Usually, the bitrate is determined at the encoding/transcoding step. Non-consistent resulting bitrate issue with Amazon transcoder might be caused by incorrect options. If you need constant bitrate (more exactly, hard maximum bitrate) you must not use constant quality mode (usual default mode).

For calculating bandwidth of already encoded movie file, there are various analysis tools. You can find more information by Googling 'bitrate calculator'.