Fix for exception on streaming on last chunk

[gorkemgoknar]

When last chunk is smaller than overlap length it raises exception with following error

The size of tensor a (0) must match the size of tensor b (1024) at non-singleton dimension 0

[erogol]

@gorkemgoknar when is the last chunk empty?

[gorkemgoknar]

@erogol it does not happen always so hard to 100% reproduce, like 1/10 chance due to non-determinism, but when happens it causes a runtime exception.

File ~/.local/lib/python3.10/site-packages/TTS/tts/models/xtts.py:673, in Xtts.handle_chunks(self, wav_gen, wav_gen_prev, wav_overlap, overlap_len)
671 if wav_overlap is not None:
672 crossfade_wav = wav_chunk[:overlap_len]
--> 673 crossfade_wav = crossfade_wav * torch.linspace(0.0, 1.0, overlap_len).to(crossfade_wav.device)
674 wav_chunk[:overlap_len] = wav_overlap * torch.linspace(1.0, 0.0, overlap_len).to(wav_overlap.device)
675 wav_chunk[:overlap_len] += crossfade_wav

RuntimeError: The size of tensor a (0) must match the size of tensor b (1024) at non-singleton dimension 0

This solution tested locally.

[erogol]

@gorkemgoknar is the problem being last chunk empty or last chunk smaller than the overlap

[gorkemgoknar]

last chunk smaller than the overlap

last chunk smaller than the overlap, not actually empty correct.