       obj.entrySizes = @entrySizes
     return obj
 
-# stco: index of each chunk
+# stco: chunk offsets relative to the beginning of the file
 class ChunkOffsetBox extends Box
   read: (buf) ->
     bits = new Bits buf

      @chunkOffsets.push bits.read_uint32()
    return

  getChunkOffset: (chunkNumber) ->
    if (chunkNumber <= 0) or (chunkNumber > @chunkOffsets.length)
      throw new Error "Chunk number of out of range: #{chunkNumber}"

    obj.sampleNumbers = @sampleNumbers
    return obj

# stsc: number of samples for each chunk
class SampleToChunkBox extends Box
  read: (buf) ->
    bits = new Bits buf
