This isn’t the first time this particular quirk has come up [1]. Unfortunately, there isn’t a setting in Asterisk to tell it to strip or otherwise alter the transmitted maxptime header. It will generally always send whatever the value is defined for the negotiated format, which is usually whatever is defined in codec_builtin.c. For g722, that’s currently set to 150.
static struct ast_codec g722 = {
.name = "g722",
.description = "G722",
.type = AST_MEDIA_TYPE_AUDIO,
.sample_rate = 16000,
.minimum_ms = 10,
.maximum_ms = 150,
.default_ms = 20,
.minimum_bytes = 80,
.samples_count = g726_samples,
.get_length = g726_length,
.smooth = 1,
};
You could change that value, recompile Asterisk, and see if that alleviate’s your issues with your provider.