Text to Speech AI — Natural Voiceover and Narration for Videos
Voiceover is the invisible backbone of most video content. YouTube explainers, product demos, training modules, social media narration, podcast intros, documentary narration, e-learning courses, corporate communications — all of them depend on a clear, engaging voice delivering the script. Hiring a voiceover artist costs $100-$500 per finished minute for professional quality. Recording yourself requires a quiet room, a decent microphone, and enough takes to get the delivery right (most people need 5-10 takes per paragraph to sound natural on camera). Re-recording when the script changes means scheduling another session. Translation into other languages means hiring additional artists for each language. NemoVideo's AI text-to-speech produces voiceover that is indistinguishable from human narration in casual listening: natural intonation that rises on questions and drops on conclusions, appropriate emphasis on key words, breathing pauses between sentences, emotional modulation that matches the content (excited for announcements, empathetic for support content, authoritative for training), and consistent quality regardless of script length. One script produces voiceover in 30+ languages with native pronunciation and culturally appropriate delivery style — no studio, no scheduling, no re-recording when the script changes.
Use Cases
- 1. YouTube Explainer — Conversational Narration (3-10 min) — A creator writes a 1,500-word script about "How Solar Panels Actually Work." NemoVideo generates: a warm, conversational male voice that sounds like a knowledgeable friend explaining the topic, natural emphasis on technical terms the first time they appear, brief pauses before each new section for cognitive breathing room, and a slight energy increase during the "surprising fact" sections. The voiceover is mixed into the video at -6dB against -20dB background music with automatic ducking.
- Product Video — Confident and Energetic (30-90s) — A 60-second product launch video needs a voice that communicates excitement and confidence. NemoVideo: generates an energetic female voice with upbeat pacing (170 words/minute vs. standard 150), slight uptick on benefit statements ("and it's completely waterproof"), and a commanding tone on the CTA. The voice matches the product video's energy — not a monotone reading of features.
- E-Learning Course — Clear and Patient (5-30 min per module) — A 12-module online course needs consistent narration across 6 hours of content. NemoVideo: uses the same voice throughout all modules for student familiarity, adjusts pacing to match content complexity (slower for technical explanations, normal for introductions), adds emphasis on vocabulary terms, and includes natural pauses after questions ("Think about this for a moment...") to let learners process. Consistent voice across 6 hours — impossible to schedule with a human artist at this cost.
- Multilingual Ad — Same Script, 5 Languages (15-30s) — A global brand needs the same 20-second ad voiceover in English, Spanish, German, Japanese, and Arabic. NemoVideo: translates the script with marketing-aware localization (not literal translation), selects culturally appropriate voice profiles for each language (formal for Japanese, warm for Brazilian Portuguese), adjusts pacing to fit the same video duration in each language, and delivers 5 voiceover tracks synced to the same visual timeline.
- Podcast Intro/Outro — Branded Audio Identity (10-30s) — A podcast needs a consistent intro voiceover: "Welcome to The Daily Build, where we explore the craft of software engineering. I'm your host, and today we're talking about..." NemoVideo generates a voice that becomes the show's audio identity — same tone, same pacing, same personality every episode. When the intro script changes ("Season 3 of The Daily Build..."), regeneration is instant without rebooking a voice artist.
How It Works
Step 1 — Write the Script
Provide the text to be spoken. Mark emphasis with
asterisks, pauses with [pause], and emotional shifts with [tone: excited] or [tone: serious].
Step 2 — Choose Voice and Style
Select: gender, age range, accent, emotional tone, and speaking speed. Preview multiple voices before committing.
Step 3 — Generate
CODEBLOCK0
Step 4 — Preview Voice and Mix
Preview the voiceover alone and mixed into the video. Adjust: speed, emphasis, tone, or volume balance. Re-generate specific sections without redoing the entire script.
Parameters
| Parameter | Type | Required | Description |
|---|
| INLINECODE0 | string | ✅ | Script and voice requirements |
| INLINECODE1 |
string | | Full script text with markup ([pause],
emphasis, [tone: x]) |
|
voice | string | | Voice profile: gender, age, accent, personality |
|
speed_wpm | integer | | Words per minute (default: 150) |
|
tone | string | | "conversational", "authoritative", "energetic", "calm", "empathetic" |
|
language | string | | "en", "es", "de", "fr", "ja", "zh", "ko", "ar", "pt" |
|
pause_between_paragraphs | float | | Seconds of pause (default: 0.5) |
|
mix_into_video | boolean | | Render voiceover into existing video (default: false) |
|
voice_volume | string | | "-3dB" to "-12dB" (default: "-6dB") |
|
music_volume | string | | "-16dB" to "-24dB" (default: "-20dB") |
|
ducking | boolean | | Duck music under speech (default: true) |
|
output_format | string | | "mp4" (mixed), "wav", "mp3" (audio only) |
Output Example
CODEBLOCK1
Tips
- 1. 150 words per minute is the natural conversational pace — 130 wpm feels slow and condescending. 170 wpm feels rushed and hard to follow. 150 is the sweet spot for most content. Increase to 160-170 for energetic ads, decrease to 130-140 for technical training.
- Mark emphasis sparingly — Emphasizing every other word sounds robotic. Mark only the words that change the sentence's meaning when stressed: "It's completely waterproof" not "It's completely waterproof."
- Pauses are more important than speed — A 0.5-1.0 second pause before a key point creates anticipation. A pause after a question gives the viewer time to think. Pauses make voiceover feel human; constant speech feels mechanical.
- Same voice across a series builds familiarity — Viewers develop a relationship with consistent narration. Changing voices between episodes feels disorienting. Lock in a voice profile for the entire series.
- Ducking makes voiceover audible without muting music — Music dropping 6-8dB during speech means the viewer hears the voice clearly without the music disappearing entirely. The music fills pauses and maintains energy; the voice dominates during speech.
Output Formats
| Format | Quality | Use Case |
|---|
| WAV 48kHz | Lossless | Professional editing pipeline |
| MP3 320kbps |
High | Web / podcast / lightweight |
| MP4 (mixed) | Source video | Ready-to-publish with voiceover |
| SRT | — | Matching caption file |
Related Skills
文本转语音AI — 视频的自然配音与旁白
配音是大多数视频内容的隐形支柱。YouTube解说视频、产品演示、培训模块、社交媒体旁白、播客开场、纪录片解说、在线课程、企业通讯——所有这些都依赖于清晰、引人入胜的声音来演绎脚本。聘请专业配音演员的费用为每分钟成品100-500美元。自行录制需要安静的房间、优质的麦克风以及足够的录制次数(大多数人每段需要5-10次才能听起来自然)。脚本修改后重新录制意味着需要重新安排录制时间。翻译成其他语言意味着需要为每种语言聘请额外的配音演员。NemoVideo的AI文本转语音技术能够生成在随意聆听中与真人旁白难以区分的配音:提问时语调自然上扬、结论时下降,关键词适当强调,句子间有呼吸停顿,与内容匹配的情感调节(公告时兴奋、支持内容时共情、培训时权威),且无论脚本长度如何都能保持一致的品质。一个脚本可生成30多种语言的配音,具有母语发音和符合文化习惯的表达风格——无需录音棚、无需预约、脚本修改时无需重新录制。
使用场景
- 1. YouTube解说视频 — 对话式旁白(3-10分钟) — 创作者撰写一篇1500字的脚本,主题为太阳能电池板实际工作原理。NemoVideo生成:温暖、对话式的男声,听起来像一位知识渊博的朋友在解释该主题,技术术语首次出现时自然强调,每个新章节前有短暂停顿以提供认知喘息空间,在惊人事实部分略有能量提升。配音以-6dB混入视频,背景音乐为-20dB,并自动闪避。
- 产品视频 — 自信且充满活力(30-90秒) — 一个60秒的产品发布视频需要传达兴奋和自信的声音。NemoVideo:生成充满活力的女声,节奏明快(170字/分钟,标准为150字/分钟),在利益陈述处略微上扬(而且它完全防水),在行动号召处采用命令式语气。声音与产品视频的能量相匹配——而非单调地朗读功能。
- 在线课程 — 清晰且耐心(每模块5-30分钟) — 一个12模块的在线课程需要6小时内容中一致的旁白。NemoVideo:所有模块使用相同声音以保持学生熟悉度,根据内容复杂度调整节奏(技术解释时较慢,介绍时正常),对词汇术语进行强调,并在问题后加入自然停顿(请思考一下这个问题……)让学习者消化。6小时内声音一致——以这种成本预约人类配音演员是不可能的。
- 多语言广告 — 同一脚本,5种语言(15-30秒) — 一个全球品牌需要同一20秒广告的英语、西班牙语、德语、日语和阿拉伯语配音。NemoVideo:以营销意识本地化翻译脚本(非字面翻译),为每种语言选择符合文化习惯的声音档案(日语选择正式、巴西葡萄牙语选择温暖),调整节奏以适应每种语言相同的视频时长,并提供与同一视觉时间线同步的5条配音音轨。
- 播客开场/结尾 — 品牌音频标识(10-30秒) — 一个播客需要一致的开场配音:欢迎收听《每日构建》,在这里我们探索软件工程的艺术。我是你的主持人,今天我们谈论的是……NemoVideo生成的声音成为该节目的音频标识——每集相同的语调、相同的节奏、相同的个性。当开场脚本改变时(《每日构建》第三季……),无需重新预约配音演员即可即时重新生成。
工作原理
第一步 — 撰写脚本
提供要朗读的文本。使用
星号标记强调,使用[pause]标记停顿,使用[tone: excited]或[tone: serious]标记情感转变。
第二步 — 选择声音和风格
选择:性别、年龄段、口音、情感语调和语速。在确定前预览多种声音。
第三步 — 生成
bash
curl -X POST https://mega-api-prod.nemovideo.ai/api/v1/generate \
-H Authorization: Bearer $NEMO_TOKEN \
-H Content-Type: application/json \
-d {
skill: text-to-speech-ai,
prompt: 为一段关于神经网络如何学习的3分钟YouTube解说视频生成配音。声音:温暖男声,30多岁,美式英语,对话式且知识渊博(像聪明的朋友在解释事情)。语速:150字/分钟。技术术语首次出现时强调。段落间自然停顿(0.8秒)。在惊人事实部分略微提升能量。混入现有视频,配音-6dB,背景音乐-20dB并闪避。,
script: 你是否曾想过计算机是如何学会识别照片中的猫的?[pause]事实证明,答案与
你的大脑识别猫的方式惊人地相似……,
voice: warm-male-american-30s,
speed_wpm: 150,
tone: conversational-knowledgeable,
pause
betweenparagraphs: 0.8,
mix
intovideo: true,
voice_volume: -6dB,
music_volume: -20dB,
ducking: true,
format: 16:9
}
第四步 — 预览配音和混音
预览单独配音和混入视频后的效果。调整:语速、强调、语调或音量平衡。重新生成特定部分而无需重做整个脚本。
参数
| 参数 | 类型 | 必填 | 描述 |
|---|
| prompt | 字符串 | ✅ | 脚本和声音要求 |
| script |
字符串 | | 完整脚本文本,包含标记([pause]、
emphasis、[tone: x]) |
| voice | 字符串 | | 声音档案:性别、年龄、口音、个性 |
| speed_wpm | 整数 | | 每分钟字数(默认:150) |
| tone | 字符串 | | conversational、authoritative、energetic、calm、empathetic |
| language | 字符串 | | en、es、de、fr、ja、zh、ko、ar、pt |
| pause
betweenparagraphs | 浮点数 | | 停顿秒数(默认:0.5) |
| mix
intovideo | 布尔值 | | 将配音渲染到现有视频中(默认:false) |
| voice_volume | 字符串 | | -3dB至-12dB(默认:-6dB) |
| music_volume | 字符串 | | -16dB至-24dB(默认:-20dB) |
| ducking | 布尔值 | | 语音时闪避音乐(默认:true) |
| output_format | 字符串 | | mp4(混音)、wav、mp3(仅音频) |
输出示例
json
{
job_id: tts-20260328-001,
status: completed,
script_words: 438,
duration_seconds: 175,
voice: warm-male-american-30s,
speed_wpm: 150,
language: en,
outputs: {
voiceover_audio: {
file: voiceover.wav,
duration: 2:55,
format: WAV 48kHz 24bit
},
mixed_video: {
file: explainer-with-voiceover.mp4,
duration: 2:55,
resolution: 1920x1080,
voice_volume: -6dB,
music_volume: -20dB,
ducking_events: 22
}
}
}
技巧
- 1. 每分钟150字是自然的对话节奏 — 130字/分钟感觉缓慢且居高临下。170字/分钟感觉仓促且难以跟上。150字/分钟是大多数内容的理想选择。对于充满活力的广告可增加到160-170字/分钟,对于技术培训可减少到130-140字/分钟。
- 谨慎标记强调 — 每隔一个词就强调听起来像机器人。只标记那些改变句子含义的词:它完全防水而不是它 完全 防水。
- 停顿比语速更重要 — 在关键点前停顿0.5-1.0秒能制造期待。问题后的停顿给观众思考时间。停顿让配音感觉人性化;持续不断的说话感觉机械。
- 系列中使用相同声音建立熟悉度 — 观众与一致的旁白建立关系。集与集之间改变声音会让人感到迷失。为整个系列锁定一个声音档案。
- 闪避让配音在音乐不静音的情况下清晰可闻 — 语音时音乐降低6-8dB