Concept for switching of sampling rates at audio processing devices

Method for operating an audio decoder device for decoding a bitstream, the method comprising:

• producing a decoded audio frame from the bitstream using a predictive decoder, wherein the predictive decoder comprises a parameter decoder for producing one or more audio parameters for the decoded audio frame from the bitstream and wherein the predictive decoder comprises a synthesis filter device for producing the decoded audio frame by synthesizing the one or more audio parameters for the decoded audio frame;
• providing a memory device comprising one or more memories, wherein each of the memories is configured to store a memory state for the decoded audio frame, wherein the memory state for the decoded audio frame of the one or more memories is used by the synthesis filter device for synthesizing the one or more audio parameters for the decoded audio frame;
• determining the memory state for the decoded audio frame, which comprises a sampling rate, for one or more of said memories by resampling a preceding memory state for synthesizing one or more audio parameters for a preceding decoded audio frame, which comprises a preceding sampling rate being different from the sampling rate of the decoded audio frame, for one or more of said memories;
• and
• storing the memory state for the decoded audio frame for one or more of said memories into the one or more of said memories;
• storing a synthesis filter memory state for determining one or more synthesis filter parameters for the decoded audio frame into a synthesis filter memory of the one or more memories;
• determining, by using a memory state resampling device, the synthesis filter memory state for determining the one or more synthesis filter parameters for the decoded audio frame by resampling a preceding synthesis memory state for determining of one or more synthesis filter parameters for the preceding decoded audio frame;
• storing, by using the memory state resampling device, the synthesis memory state for determining of the one or more synthesis filter parameters for the decoded audio frame into the synthesis filter memory;
• wherein a number of samples in the preceding synthesis memory state is calculated according to the formula MemSynRSizeOld=(int)(TI*fs1);
• wherein a number of samples in the synthesis memory state is calculated according to the formula MemSynRSizeNew=(int)(TI*fs2);
• wherein MemSynRSizeOld is the number of samples in the preceding synthesis memory state, wherein MemSynRSizeNew is the number of samples in the synthesis memory state, wherein fs1 is the preceding sampling rate, wherein fs2 is the sampling rate, wherein TI is a largest possible duration to be covered by the preceding syntheses filter memory state and by the syntheses filter memory state.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for operating an audio decoder device for decoding a bitstream, the method comprising:

• producing a decoded audio frame from the bitstream using a predictive decoder, wherein the predictive decoder comprises a parameter decoder for producing one or more audio parameters for the decoded audio frame from the bitstream and wherein the predictive decoder comprises a synthesis filter device for producing the decoded audio frame by synthesizing the one or more audio parameters for the decoded audio frame;
• providing a memory device comprising one or more memories, wherein each of the memories is configured to store a memory state for the decoded audio frame, wherein the memory state for the decoded audio frame of the one or more memories is used by the synthesis filter device for synthesizing the one or more audio parameters for the decoded audio frame;
• determining the memory state for the decoded audio frame, which comprises a sampling rate, for one or more of said memories by resampling a preceding memory state for synthesizing one or more audio parameters for a preceding decoded audio frame, which comprises a preceding sampling rate being different from the sampling rate of the decoded audio frame, for one or more of said memories;
• and
• storing the memory state for the decoded audio frame for one or more of said memories into the one or more of said memories;
• storing a synthesis filter memory state for determining one or more synthesis filter parameters for the decoded audio frame into a synthesis filter memory of the one or more memories;
• determining, by using a memory state resampling device, the synthesis filter memory state for determining the one or more synthesis filter parameters for the decoded audio frame by resampling a preceding synthesis memory state for determining of one or more synthesis filter parameters for the preceding decoded audio frame;
• storing, by using the memory state resampling device, the synthesis memory state for determining of the one or more synthesis filter parameters for the decoded audio frame into the synthesis filter memory;
• wherein a number of samples in the preceding synthesis memory state is calculated according to the formula MemSynRSizeOld=(int)(TI*fs1);
• wherein a number of samples in the synthesis memory state is calculated according to the formula MemSynRSizeNew=(int)(TI*fs2);
• wherein MemSynRSizeOld is the number of samples in the preceding synthesis memory state, wherein MemSynRSizeNew is the number of samples in the synthesis memory state, wherein fs1 is the preceding sampling rate, wherein fs2 is the sampling rate, wherein TI is a largest possible duration to be covered by the preceding syntheses filter memory state and by the syntheses filter memory state,
• when said computer program is run by a computer.

Audio encoder device for encoding a framed audio signal, the audio encoder device comprising:

• a predictive encoder for producing an encoded audio frame from the framed audio signal, wherein the predictive encoder comprises a parameter analyzer for producing one or more audio parameters for the encoded audio frame from the framed audio signal and wherein the predictive encoder comprises a synthesis filter device for producing a decoded audio frame by synthesizing one or more audio parameters for the decoded audio frame, wherein the one or more audio parameters for the decoded audio frame are the one or more audio parameters for the encoded audio frame;
• a memory device comprising one or more memories, wherein each of the memories is configured to store a memory state for the decoded audio frame, wherein the memory state for the decoded audio frame of the one or more memories is used by the synthesis filter device for synthesizing the one or more audio parameters for the decoded audio frame;
• and
• a memory state resampling device configured to determine the memory state for the decoded audio frame, which comprises a sampling rate, for one or more of said memories by resampling a preceding memory state for synthesizing one or more audio parameters for a preceding decoded audio frame, which comprises a preceding sampling rate being different from the sampling rate of the decoded audio frame, for one or more of said memories and to store the memory state for the decoded audio frame for one or more of said memories into the one or more of said memories;
• wherein the one or more memories comprise a synthesis filter memory configured to store a synthesis filter memory state for determining one or more synthesis filter parameters for the decoded audio frame, wherein the memory state resampling device is configured to determine the synthesis filter memory state for determining the one or more synthesis filter parameters for the decoded audio frame by resampling a preceding synthesis memory state for determining of one or more synthesis filter parameters for the preceding decoded audio frame and to store the synthesis memory state for determining of the one or more synthesis filter parameters for the decoded audio frame into the synthesis filter memory;
• wherein a number of samples in the preceding synthesis memory state is calculated according to the formula MemSynRSizeOld=(int)(TI*fs1);
• wherein a number of samples in the synthesis memory state is calculated according to the formula MemSynRSizeNew=(int)(TI*fs2);
• wherein MemSynRSizeOld is the number of samples in the preceding synthesis memory state, wherein MemSynRSizeNew is the number of samples in the synthesis memory state, wherein fs1 is the preceding sampling rate, wherein fs2 is the sampling rate, wherein TI is a largest possible duration to be covered by the preceding syntheses filter memory state and by the syntheses filter memory state.

Method for operating an audio encoder device for encoding a framed audio signal, the method comprising:

• producing an encoded audio frame from the framed audio signal using a predictive encoder, wherein the predictive encoder comprises a parameter analyzer for producing one or more audio parameters for the encoded audio frame from the framed audio signal and wherein the predictive encoder comprises a synthesis filter device for producing a decoded audio frame by synthesizing one or more audio parameters for the decoded audio frame, wherein the one or more audio parameters for the decoded audio frame are the one or more audio parameters for the encoded audio frame;
• providing a memory device comprising one or more memories, wherein each of the memories is configured to store a memory state for the decoded audio frame, wherein the memory state for the decoded audio frame of the one or more memories is used by the synthesis filter device for synthesizing the one or more audio parameters for the decoded audio frame;
• determining the memory state for the decoded audio frame, which comprises a sampling rate, for one or more of said memories by resampling a preceding memory state for synthesizing one or more audio parameters for a preceding decoded audio frame, which comprises a preceding sampling rate being different from the sampling rate of the decoded audio frame, for one or more of said memories;
• and
• storing the memory state for the decoded audio frame for one or more of said memories into the one or more of said memories;
• storing a synthesis filter memory state for determining one or more synthesis filter parameters for the decoded audio frame into a synthesis filter memory of the one or more memories;
• determining, by using a memory state resampling device, the synthesis filter memory state for determining the one or more synthesis filter parameters for the decoded audio frame by resampling a preceding synthesis memory state for determining of one or more synthesis filter parameters for the preceding decoded audio frame;
• storing, by using the memory state resampling device, the synthesis memory state for determining of the one or more synthesis filter parameters for the decoded audio frame into the synthesis filter memory;
• wherein a number of samples in the preceding synthesis memory state is calculated according to the formula MemSynRSizeOld=(int)(TI*fs1);
• wherein a number of samples in the synthesis memory state is calculated according to the formula MemSynRSizeNew=(int)(TI*fs2);
• wherein MemSynRSizeOld is the number of samples in the preceding synthesis memory state, wherein MemSynRSizeNew is the number of samples in the synthesis memory state, wherein fs1 is the preceding sampling rate, wherein fs2 is the sampling rate, wherein TI is a largest possible duration to be covered by the preceding syntheses filter memory state and by the syntheses filter memory state.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for operating an audio encoder device for encoding a framed audio signal, the method comprising:

• producing an encoded audio frame from the framed audio signal using a predictive encoder, wherein the predictive encoder comprises a parameter analyzer for producing one or more audio parameters for the encoded audio frame from the framed audio signal and wherein the predictive encoder comprises a synthesis filter device for producing a decoded audio frame by synthesizing one or more audio parameters for the decoded audio frame, wherein the one or more audio parameters for the decoded audio frame are the one or more audio parameters for the encoded audio frame;
• providing a memory device comprising one or more memories, wherein each of the memories is configured to store a memory state for the decoded audio frame, wherein the memory state for the decoded audio frame of the one or more memories is used by the synthesis filter device for synthesizing the one or more audio parameters for the decoded audio frame;
• determining the memory state for the decoded audio frame, which comprises a sampling rate, for one or more of said memories by resampling a preceding memory state for synthesizing one or more audio parameters for a preceding decoded audio frame, which comprises a preceding sampling rate being different from the sampling rate of the decoded audio frame, for one or more of said memories;
• and
• storing the memory state for the decoded audio frame for one or more of said memories into the one or more of said memories;
• storing a synthesis filter memory state for determining one or more synthesis filter parameters for the decoded audio frame into a synthesis filter memory of the one or more memories;
• determining, by using a memory state resampling device, the synthesis filter memory state for determining the one or more synthesis filter parameters for the decoded audio frame by resampling a preceding synthesis memory state for determining of one or more synthesis filter parameters for the preceding decoded audio frame;
• storing, by using the memory state resampling device, the synthesis memory state for determining of the one or more synthesis filter parameters for the decoded audio frame into the synthesis filter memory;
• wherein a number of samples in the preceding synthesis memory state is calculated according to the formula MemSynRSizeOld=(int)(TI*fs1);
• wherein a number of samples in the synthesis memory state is calculated according to the formula MemSynRSizeNew=(int)(TI*fs2);
• wherein MemSynRSizeOld is the number of samples in the preceding synthesis memory state, wherein MemSynRSizeNew is the number of samples in the synthesis memory state, wherein fs1 is the preceding sampling rate, wherein fs2 is the sampling rate, wherein TI is a largest possible duration to be covered by the preceding syntheses filter memory state and by the syntheses filter memory state,
• when said computer program is run by a computer.