Gemini 2.5 PRO vs Deepseek v3.1 vs QWEN3-Max-Preview vs CHATGPT5

Comprehensive Review: Comparing Leading Language Models for Subtitle Transcription and Translation

In the rapidly evolving realm of AI-powered language processing, selecting the right tool for transcription and translation tasks can be pivotal. Recently, I undertook an informal comparison of four prominent language models—Gemini 2.5 PRO, Deepseek v3.1, QWEN3-Max-Preview, and ChatGPT-5—to evaluate their effectiveness in converting English transcripts into bilingual subtitles, specifically Mandarin Chinese. While this assessment is unscientific and anecdotal, it offers valuable insights into each model’s strengths and limitations.

Background and Task Overview

My task involved translating a typical subtitle file (.srt format) for a 5-10 minute video containing approximately 150-250 lines. The goal was to generate accurate, synchronized bilingual subtitles, maintaining proper timestamps and high translation quality. Historically, I relied on Gemini 2.5 Flash for this purpose; however, over the past couple of weeks, I noticed increasing discrepancies in timestamp accuracy and translation fidelity.

Evaluation of Each Tool

Gemini 2.5 Flash (Free User)

Initially, Gemini 2.5 Flash served as my go-to tool. It efficiently handled basic transcription tasks, but recent updates introduced significant issues. Timestamps became inconsistent—adding unnecessary minutes and causing misalignment in the final subtitles. Efforts to manually correct timestamps or process the transcript in smaller segments became necessary, which is time-consuming. The translation quality was mediocre, approximately a 6.5/10, occasionally missing colloquial expressions and failing to grasp the broader context, translating line-by-line rather than holistically.

Gemini 2.5 PRO

Switching to Gemini 2.5 PRO improved the metadata accuracy. Timestamps remained intact, and the translation quality improved marginally. However, it still struggled with nuanced expressions, and its handling of context remained imperfect. Overall, the output was serviceable but left room for improvement.

ChatGPT-5 (Plus Subscription)

Despite high expectations, ChatGPT-5 proved unreliable for this task. Its conversational interface limits processing to roughly 50 lines, and attempts to continue the translation often resulted in hallucinations, incomplete outputs, or deviations—such as generating separate, fragmented documents. This makes it less suitable for lengthy subtitle files requiring contextual consistency.

Deepseek v3.1

Deepseek demonstrated decent timestamp management, with only minor alignment issues. It translated about an 8/10, though