Batch Translation Support for DeepSeek

[rtalmaci]

Feature Request: Batch Translation Support for DeepSeek

Summary

Add support for batch translation in DeepSeekService by implementing the IBatchTranslationService interface.

Proposed Implementation

• Interface Implementation: Update DeepSeekService to implement IBatchTranslationService.
• Initialization: Update InitializeAsync to load retry settings (MaxRetries, RetryDelay, RetryDelayMultiplier) from configuration.
• Batch Logic:
  • Implement TranslateBatchAsync with a retry loop handling TooManyRequests (429) and ServiceUnavailable (503) status codes.
  • Implement TranslateBatchWithDeepSeekApi using DeepSeek's JSON mode (response_format: { type: "json_object" }).
  • Use a specialized prompt to instruct the model to return a structured JSON response containing an array of translated items with their original positions.
  • Deserialize the response into StructuredBatchResponse and merge using the base MergeByPosition helper.

Benefits

• Reduction in API calls for large subtitle files.
• (Maybe) Improved translation consistency by providing multiple lines in a single context.

I can open PR with the changes

[rowanfuchs]

The thing is, the DeepSeek docs indicate that the feature isn't reliable, it suffers from empty content, truncation, etc. The feature I'm waiting for to add batching is structured output, like the other services offer. Otherwise you're shipping a feature that looks like an optimization but introduces reliability regressions that are hard to trace back to their root cause.

[rtalmaci]

I understand and totally makes sense. I'll run some tests locally to see if their JSON output is of any use and report back if i find anything useful.