Adaptive real-time transcoding method and streaming server therefor

1. An adaptive real-time transcoding method for segmenting, at a streaming server, media data into media data segments, transcoding the media data segments, and sequentially transmitting the media data segments to a client end over a network, the method comprising:

determining a fill level of a playback buffer of the client end by comparing a sum of playback times of transmitted media data segments with an elapse time from a streaming start time;

determining a quality of a media data segment that is not transmitted to the client end, based on the fill level of the playback buffer; and

transcoding the non-transmitted media data segment based on the determined quality.

2. The method of claim 1 , further comprising:

temporarily storing the segmented and transcoded media data segments in a transcoding buffer,

wherein the transcoding comprises:

extracting a media data segment stored in the transcoding buffer; and

re-transcoding the extracted media data segment based on the determined quality.

3. An adaptive real-time transcoding method comprising:

segmenting, at a streaming server, media data into media data segments and transcoding the media data segments; and

sequentially transmitting, at the stream server, the media data segments to a client end over a network,

wherein a quality of each of the media data segments is tuned in real time at the streaming server based on a fill level of a playback buffer of the client end, and

wherein the fill level of the playback buffer is determined by comparing a sum of playback times of transmitted data segments with an elapse dine from a streaming start time.

4. The method of claim 3 , wherein each of the media data segments includes a playback time and quality data in a header as metadata, and

the quality data includes information about the real-time tuned quality.

5. The method according to claim 1 , wherein the fill level of the playback buffer is a reference value used at the streaming server to estimate whether the playback buffer is empty or whether the playback buffer becomes to be empty after a preset period of time is elapsed.

6. The method of claim 1 , wherein, in response to the sum of playback times of transmitted media data segments being detected to be less than or equal to the elapse time from the streaming start time, the streaming server transcodes the media data segment at a quality lower than the quality of the transmitted media data segment.

7. The method of claim 1 , wherein, in response to the sum of playback times of transmitted media data segments being greater than the elapse time of the streaming start time, the streaming server alters a tuning ratio of each quality based on an additional elapse time from a point in time at which the sum of playback times of transmitted media data segments is detected to be less than or equal to the streaming start time.

8. The method of claim 7 , wherein the streaming server finely tunes the quality in response to the additional elapse time being greater than a threshold reference, and tunes the quality at a relatively high tuning ratio in response to the additional elapse time being less than the threshold reference.

9. A streaming server for sequentially transmitting media data segments to a playback buffer of a client end for a streaming service, the streaming server comprising:

a playback buffer estimator configured to determine a fill level of the playback buffer of the client end by comparing a sum of playback times of transmitted media data segments with an elapse time from a streaming start time;

a quality controller configured to determine a quality of a media data segment that is not transmitted to the client end, based on the fill level of the playback buffer; and

a transcoder configured to transcode the non-transmitted media data segment based on the determined quality.

10. The streaming server of claim 9 , further comprising:

a transcoding buffer configured to temporarily store media data segments corresponding to a transcoding result of the transcoder,

wherein the transcoder is configured to extract a media data segment stored in the transcoding buffer, and to re-transcode the extracted media data segment based on the determined quality.

11. The streaming server of claim 9 , wherein the fill level of the playback buffer is a reference value used at the streaming server to estimate whether the playback buffer is empty or whether the playback buffer becomes to be empty after a preset period of time is elapsed.

12. The method according to claim 3 , wherein the fill level of the playback buffer is a reference value used at the streaming server to estimate whether the playback buffer is empty or whether the playback buffer becomes to be empty after a preset period of time is elapsed.

13. The method of claim 3 , wherein, in response to the sum of playback times of transmitted media data segments being detected to be less than or equal to the elapse time from the streaming start time, the streaming server transcodes the media data segment at a quality lower than the quality of the transmitted media data segment.

14. The method of claim 3 , wherein, in response to the sum of playback times of transmitted media data segments being greater than the elapse time of the streaming start time, the streaming server alters a tuning ratio of each quality based on an additional elapse time from a point in time at which the sum of playback times of transmitted media data segments is detected to be less than or equal to the streaming start time.

15. The method of claim 14 , wherein the streaming server finely tunes the quality in response to the additional elapse time being greater than a threshold reference, and tunes the quality at a relatively high tuning ratio in response to the additional elapse time being less than the threshold reference.