Generating and distributing a replacement playlist

1. A method comprising:

receiving, by a client device, a first playlist, wherein the first playlist was sent by a server device over a wide area network, wherein the first playlist includes references to a first plurality of audio files in a first specified order, wherein playout of the first plurality of audio files has a first duration;

in response to receiving the first playlist, causing, by the client device, an audio player application executing on the client device to retrieve and play out at least some of the first plurality of audio files in the first specified order;

while the client device is playing out a current audio file of the first plurality of audio files, receiving, by the client device, an instruction specifying that a sleep timer has been activated with a target duration;

in response to receiving the instruction, transmitting, by the client device to the server device, an indication that the sleep timer has been activated with the target duration;

receiving, by the client device, a second playlist from the server device, wherein the second playlist includes references to a second plurality of audio files in a second specified order, wherein playout of the second plurality of audio files has a second duration that is: less than the first duration and within a threshold duration of the target duration; and

in response to receiving the second playlist, causing, by the client device, the audio player application to, after playout of the current audio file completes, stop playing out audio files from the first plurality of audio files and retrieve and play out the second plurality of audio files in the second specified order.

2. The method of claim 1 , wherein the second plurality of audio files does not include any audio files of the first plurality of audio files that are before the current audio file in the first specified order.

3. The method of claim 1 , wherein the second plurality of audio files includes at least some audio files of the first plurality of audio files that are after the current audio file in the first specified order.

4. The method of claim 3 , wherein the audio files in the first plurality of audio files are each associated with a higher priority or a lower priority, and wherein the second plurality of audio files includes audio files from the first plurality of audio files associated with the higher priority.

5. The method of claim 4 , wherein audio files containing advertisements are associated with the higher priority and audio files containing music are associated with the lower priority.

6. The method of claim 1 , wherein the threshold duration is three minutes or less.

7. The method of claim 1 , wherein the second duration is based on the target duration minus any time remaining for playout of the current audio file.

8. The method of claim 1 , wherein the second plurality of audio files includes audio files with (i) slower tempos, (ii) narrower dynamic ranges, or (iii) lower volumes than the first plurality of audio files.

9. The method of claim 1 , wherein the second plurality of audio files, when played in order, gradually decrease in volume.

10. An article of manufacture including a non-transitory computer-readable medium, having stored thereon program instructions that, upon execution by a client device, cause the client device to perform operations comprising:

receiving a first playlist, wherein the first playlist was sent by a server device over a wide area network, wherein the first playlist includes references to a first plurality of audio files in a first specified order, wherein playout of the first plurality of audio files has a first duration;

in response to receiving the first playlist, causing an audio player application executing on the client device to retrieve and play out at least some of the first plurality of audio files in the first specified order;

while the client device is playing out a current audio file of the first plurality of audio files, receiving an instruction specifying that a sleep timer has been activated with a target duration;

in response to receiving the instruction, transmitting, to the server device, an indication that the sleep timer has been activated with the target duration;

receiving a second playlist from the server device, wherein the second playlist includes references to a second plurality of audio files in a second specified order, wherein playout of the second plurality of audio files has a second duration that is: less than the first duration and within a threshold duration of the target duration; and

in response to receiving the second playlist, causing the audio player application to, after playout of the current audio file completes, stop playing out audio files from the first plurality of audio files and retrieve and play out the second plurality of audio files in the second specified order.

11. The article of manufacture of claim 10 , wherein the second plurality of audio files does not include any audio files of the first plurality of audio files that are before the current audio file in the first specified order.

12. The article of manufacture of claim 10 , wherein the second plurality of audio files includes at least some audio files of the first plurality of audio files that are after the current audio file in the first specified order.

13. The article of manufacture of claim 12 , wherein the audio files in the first plurality of audio files are each associated with a higher priority or a lower priority, and wherein the second plurality of audio files includes audio files from the first plurality of audio files associated with the higher priority.

14. The article of manufacture of claim 13 , wherein audio files containing advertisements are associated with the higher priority and audio files containing music are associated with the lower priority.

15. The article of manufacture of claim 10 , wherein the threshold duration is three minutes or less.

16. The article of manufacture of claim 10 , wherein the second duration is based on the target duration minus any time remaining for playout of the current audio file.

17. The article of manufacture of claim 10 , wherein the second plurality of audio files includes audio files with (i) slower tempos, (ii) narrower dynamic ranges, or (iii) lower volumes than the first plurality of audio files.

18. The article of manufacture of claim 10 , wherein the second plurality of audio files, when played in order, gradually decrease in volume.

19. A method comprising:

generating, by a server device, a first playlist for a client device, wherein the first playlist includes references to a first plurality of audio files in a first specified order, wherein playout of the first plurality of audio files has a first duration;

transmitting, by the server device over a wide area network, the first playlist to the client device;

receiving, by the server device, an instruction from the client device, wherein the instruction specifies that the client device has activated a sleep timer with a target duration;

generating, by the server device, a second playlist, wherein the second playlist includes references to a second plurality of audio files in a second specified order, wherein playout of the second plurality of audio files has a second duration that is: less than the first duration and within a threshold duration of the target duration; and

transmitting, by the server device over the wide area network, the second playlist to the client device.

20. The method of claim 19 , wherein the second plurality of audio files includes at least some audio files of the first plurality of audio files that are after a current audio file in the first specified order.