Amazon (NASDAQ:AMZN) saw its revenue growth rate accelerate in Q2. The top-line figure rose 20% year over year, to $63.4 billion. This is an acceleration from 17% growth in Q1. Unfortunately, lower-than-expected earnings per share for the period prompted shares to sell off a few percentage points.

Of course, there's more to the quarter than Amazon's top and bottom line. Investors who want a more holistic view of the company can turn to its second-quarter earnings call. Some notable takeaways from the call include management's commentary on one-day shipping, video advertising, and more.

Here's a look at a few insights from the call that are worth mulling over.

One-day shipping

Part of the acceleration in Amazon's second-quarter year-over-year revenue growth rate was due to the company's aggressive rollout of one-day shipping. In the company's second-quarter earnings release, management said free one-day delivery is now available on over 10 million items, helping drive revenue growth as customers respond to this enhanced convenience.

Amazon CFO Brian Olsavsky talked more about the company's progress on one-day shipping during the earnings call:

So we are really pleased with the customer response into our growing One-Day offering. In Q2, we had a meaningful step up in the One-Day shipments, primarily in North America and One-Day volume was accelerating throughout the quarter.

He added that the company is only "in the middle" of its rollout of one-day shipping as a primary default shipping option for customers. This ramp up in one-day availability will persist over the next few quarters in both North America and overseas.

Expect challenging comps for subscription revenue

Amazon's subscription-services revenue, or revenue from Prime memberships, audiobook, streaming video, e-book, digital music, and other non-Amazon Web Services subscription services, continued to see outsize growth in Q2. Subscription-services revenue increased 37% year over year during the period, or 39% when excluding the impact of foreign-exchange rates.

But this growth rate is likely to come down in the coming quarters as Amazon loses the benefit of its Prime membership price increase in the second quarter of 2018.

Amazon's price increase for its Prime membership "will be a factor that we're comping for the next 12 months," said Olsavsky. But this doesn't mean the segment will flatline. "It's offset by the growth in the Prime program itself and the expansion of Prime Benefits or the Prime program globally," the CFO explained. Of course, investors should factor in some deceleration into their forecasts, as Amazon is losing the favorable comparison from a price increase that it had over the last 12 months.

Capitalizing on the opportunity in video advertising

Amazon's "other" revenue may only account for 5% of the company's total revenue, but the segment is growing faster than overall revenue and sports a higher gross margin than Amazon's consolidated business -- so much so that management has said the segment has been a catalyst for Amazon's margin expansion in recent quarters.

What's the key reason for this impressive performance from the company's other revenue? Amazon's advertising business -- the segment's primary driver. With the help of Amazon's fast-growing advertising business, the segment saw revenue rise 37% year over year in Q2, to $3 billion.

One way management wants to keep growing its advertising revenue is by rolling out more ad-supported video content. Amazon is "expanding our video and over-the-top [OTT] offerings for brands," Olsavsky explained. Specifically, the company will continue building out its ad-supported streaming services (IMDb TV and live sports), increase ad inventory, and improve the integration of its Amazon Publisher Services technology -- a platform that helps video publishers optimize their ad spend.

While these takeaways from Amazon's earnings call offer only a glimpse of management's comments, they're certainly narratives investors should keep in mind in the coming quarters.

Can one-day shipping drive another quarter of accelerating growth? Will subscription revenue decelerate in Q3? Can Amazon keep growing its other revenue at rapid rates with the help of advertising? These are some of the questions investors may want to look for answers to in the second half of 2019.