put_buffer(&s->pb, buf, size);
put_buffer(&s->pb, pkt->data, pkt->size);
static int amr_write_packet(AVFormatContext *s, int stream_index_ptr,                           uint8_t *buf, int size, int force_pts){    put_buffer(&s->pb, buf, size);    put_flush_packet(&s->pb);    return 0;}