System and method for performing speech synthesis with a cache of phoneme sequences

1. A method of performing speech synthesis, the method comprising:

obtaining at a first time a plurality of phoneme sequences by applying a first part of a speech synthesizer to a text corpus to yield an obtained plurality of phoneme sequences, the first part of the speech synthesizer only identifying possible phoneme sequences to be used in synthesizing speech at a second time which is later than the first time;

for each respective phoneme sequence of the obtained plurality of phoneme sequences, identifying joins that would be calculated to synthesize the respective phoneme sequence; and

adding the identified joins to a cache for use in speech synthesis.

2. The method of claim 1 , the method further comprising:

recording a frequency of occurrence for each of the obtained plurality of phoneme sequences; and

pruning the cache.

3. The method of claim 1 , the method further comprising:

building a plurality of caches of different sizes based on values or parameters.

4. The method of claim 3 , wherein the values or parameters comprise computational costs or frequency of occurrence.

5. A method of synthesizing a speech signal, the method comprising:

selecting one or more acoustic units from an acoustic unit database;

determining whether a join cost of an acoustic unit sequential pair resides in a cache created by steps comprising:

obtaining at a first time a plurality of phoneme sequences by applying a first part of a speech synthesizer to a text corpus to yield an obtained plurality of phoneme sequences, the first part of the speech synthesizer only identifying possible phoneme sequences to be used in synthesizing speech at a second time which is later than the first time;

for each respective phoneme sequence of the obtained plurality of phoneme sequences, identifying joins that would be calculated to synthesize the respective-phoneme sequence; and

adding the identified joins to a cache for use in speech synthesis;

if the cache contains the join, extracting the join from the cache for use in speech synthesis; and

if the cache does not contain the join, calculating a value of the join for use in speech synthesis.

6. The method of claim 5 , wherein calculating the value of the join cost is performed to enhance accuracy over speed.

7. A system for performing speech synthesis, the system comprising:

a first module configured to obtain at a first time a plurality of phoneme sequences by applying a first part of a speech synthesizer to a text corpus to yield an obtained plurality of phoneme sequences, the first part of the speech synthesizer only identifying possible phoneme sequences to be used in synthesizing speech at a second time which is later than the first time;

a second module configured, for each respective phoneme sequence of the obtained plurality of phoneme sequences, to identify joins that would be calculated to synthesize the respective phoneme sequence; and

a third module configured to add the identified joins to a cache for use in speech synthesis.

8. The system of claim 7 , the system further comprising:

a fourth module configured to record a frequency of occurrence for each of the plurality of phoneme sequences; and

a fifth module configured to prune the cache.

9. The system of claim 7 , the system further comprising:

a fourth module configured to build a plurality of caches of different sizes based on values or parameters.

10. The system of claim 9 , wherein the values or parameters comprise computational costs or frequency of occurrence.

11. A system for synthesizing a speech signal, the system comprising:

a first module configured to select one or more acoustic units from an acoustic unit database;

a second module configured to determine whether a join cost of an acoustic unit sequential pair resides in a cache created by steps comprising:

obtaining at a first time a plurality of phoneme sequences by applying a first part of a speech synthesizer to a text corpus to yield an obtained plurality of phoneme sequences, the first part of the speech synthesizer only identifying possible phoneme sequences to be used in synthesizing speech at a second time which is later than the first time;

for each respective phoneme sequence of the obtained plurality of phoneme sequences, identifying joins that would be calculated to synthesize the respective-phoneme sequence; and

adding the identified joins to a cache for use in speech synthesis

a third module configured, if the cache contains the join, to extract the join from the cache for use in speech synthesis; and

a fourth module configured, if the cache does not contain the join, to calculate a value of the join for use in speech synthesis.

12. The system of claim 11 , wherein calculating the value of the join cost is performed to enhance accuracy over speed.

13. A non-transitory computer readable medium storing a computer program having instructions for performing speech synthesis, the instructions comprising:

obtaining at a first time a plurality of phoneme sequences by applying a first part of a speech synthesizer to a text corpus to yield an obtained plurality of phoneme sequences, the first part of the speech synthesizer only identifying possible phoneme sequences to be used in synthesizing speech at a second time which is later than the first time;

for each respective phoneme sequence of the obtained plurality of phoneme sequences, identifying joins that would be calculated to synthesize the respective phoneme sequence; and

adding the identified joins to a cache for use in speech synthesis.

14. The non-transitory computer readable medium of claim 13 , the instructions further comprising:

recording a frequency of occurrence for each of the obtained plurality of phoneme sequences; and

pruning the cache.

15. The non-transitory computer readable medium of claim 13 , the instructions further comprising:

building a plurality of caches of different sizes based on values or parameters.

16. The non-transitory computer readable medium of claim 15 , wherein the values or parameters comprise computational costs or frequency of occurrence.

17. A non-transitory computer readable medium storing a computer program having instructions for synthesizing a speech signal, the instructions comprising:

selecting one or more acoustic units from an acoustic unit database;

determining whether a join cost of an acoustic unit sequential pair resides in a cache created by steps comprising:

obtaining at a first time a plurality of phoneme sequences by applying a first part of a speech synthesizer to a text corpus to yield an obtained plurality of phoneme sequences, the first part of the speech synthesizer only identifying possible phoneme sequences to be used in synthesizing speech at a second time which is later than the first time;

for each respective phoneme sequence of the obtained plurality of phoneme sequences, identifying joins that would be calculated to synthesize the respective-phoneme sequence; and

adding the identified joins to a cache for use in speech synthesis

if the cache contains the join, extracting the join from the cache for use in speech synthesis; and

if the cache does not contain the join, calculating a value of the join for use in speech synthesis.

18. The non-transitory computer readable medium of claim 17 , wherein calculating the value of the join cost is performed to enhance accuracy over speed.