Selecting a packet loss concealment procedure
In accordance with an example embodiment of the present invention, disclosed is a method and an apparatus thereof for selecting a packet loss concealment procedure for a lost audio frame of a received audio signal. A method for selecting a packet loss concealment procedure comprises detecting an audio type of a received audio frame and determining a packet loss concealment procedure based on the audio type. In the method, detecting an audio type comprises determining a stability of a spectral envelope of signals of received audio frames.
1. A method for selecting a packet loss concealment procedure, the method being performed in an audio decoder and comprising:
detecting an audio type of a received audio frame; and
determining a packet loss concealment procedure based at least partially on the audio type, wherein detecting the audio type comprises determining a stability of a spectral envelope of signals of received audio frames.
2. The method according to claim 1 , wherein determining the stability of the spectral envelope of signals of received audio frames comprises comparing the spectral envelope of signals of at least two correctly received consecutive audio frames.
3. The method according to claim 1 , wherein determining the stability of the spectral envelope of received signals of received audio frames comprises calculating a scalar measurement related to the spectral envelope of received signals of received audio frames.
4. The method according to claim 1 , wherein detecting the audio type comprises determining the audio type to be either music or speech.
5. The method according to claim 4 , wherein detecting the audio type comprises determining the audio type to be music when the spectral envelope of received audio signals is stable and determining the audio type to be speech when the spectral envelope of received audio signals is unstable.
6. The method according to claim 4 , wherein determining the packet loss concealment procedure based at least partially on the audio type comprises selecting a sinusoidal phase evolution based packet loss concealment procedure, Phase Error Concealment Unit (ECU), responsive to determining that the audio type is music.
7. The method according to claim 4 , wherein determining the packet loss concealment procedure based at least partially on the audio type comprises selecting a pitch model, responsive to determining that the audio type is speech.
8. The method according to claim 1 , wherein determining the packet loss concealment procedure further comprises determining a second measurement of a received audio frame, and comparing the second measurement against a determined threshold.
9. The method according to claim 8 , wherein the second measurement comprises an indicator selected from the group consisting of pitch prediction gain, tilt of the spectral envelope, voice activity detector flag, power parameters, measure of a tonality of the signal, measure of how harmonic the signal is, and a measure of how spectrally complex the signal is.
10. A host device for selecting a packet loss concealment procedure, the host device comprising:
a processor; and
a memory storing instructions that, when executed by the processor, cause the host device to:
detect an audio type of a received audio frame; and
determine a packet loss concealment procedure based at least partially on the audio type, wherein detecting the audio type comprises determining a stability of a spectral envelope of signals of received audio frames.
11. The host device according to claim 10 , wherein the instructions to determine the stability of the spectral envelope of signals of received audio frames comprise instructions that, when executed by the processor, cause the host device to compare the spectral envelope of signals of at least two correctly received consecutive audio frames.
12. The host device according to claim 10 , wherein the instructions to determine the stability of the spectral envelope of received signals of received audio frames comprise instructions that, when executed by the processor, cause the host device to calculate a scalar measurement related to the spectral envelope of received signals of received audio frames.
13. The host device according to claim 10 , wherein the instructions to detect the audio type comprise instructions that, when executed by the processor, cause the host device to determine the audio type to be either music or speech.
14. The host device according to claim 13 , wherein the instructions to detect the audio type comprise instructions that, when executed by the processor, cause the host device to determine the audio type to be music when the spectral envelope of received audio signals is stable and determine the audio type to be speech when the spectral envelope of received audio signals is unstable.
15. The host device according to claim 10 , wherein the instructions to determine the packet loss concealment procedure further comprise instructions that, when executed by the processor, cause the host device to:
determine a second measurement of a received audio frame; and
compare the second measurement against a determined threshold.
16. The host device according to claim 10 , wherein the host device is a wireless terminal.
17. The host device according to claim 10 , wherein the host device is a transcoding node arranged to perform transcoding of audio.
18. A non-transitory computer readable-medium storing a computer program comprising program instructions that, when executed by processing circuitry of a host device, configured the host device to select a packet loss concealment procedure, said program instructions including instructions configuring the host device to:
detect an audio type of a received audio frame; and
determine a packet loss concealment procedure based at least partially on the audio type, wherein detecting the audio type comprises determining a stability of a spectral envelope of signals of received audio frames.