Sample digital talking book · ANSI/NISO Z39.86 · NLS Spec 1203
The Constitution of the United States of America, 1787
Built from an EPUB by a local pipeline: text parsed into navigable divisions, narrated with the Kokoro-82M (Apache 2.0) voice af_heart, mastered to EBU R128 loudness, and packaged with OPF, NCX and SMIL files. Every clip time follows the Spec 1203 timing rule, and the checks below were run on the finished files.
Download the DTB (zip) · Source code
30 minof narration
31navigation points
170synchronized clips
7.4×faster than real time
30/30checks passed
1.2%word error rate
Navigation
- title/authorThe Constitution of the United States of America, 1787tts000001-0001.mp3 · 0.500s
- prelimitemPreambletts000001-0001.mp3 · 12.480s
- chapterArticle Itts000001-0002.mp3 · 0.500s
- sectionSection 1tts000001-0002.mp3 · 2.770s
- sectionSection 2tts000001-0002.mp3 · 15.170s
- sectionSection 3tts000001-0002.mp3 · 127.680s
- sectionSection 4tts000001-0002.mp3 · 255.550s
- sectionSection 5tts000001-0002.mp3 · 285.520s
- sectionSection 6tts000001-0002.mp3 · 350.640s
- sectionSection 7tts000001-0002.mp3 · 404.890s
- sectionSection 8tts000001-0002.mp3 · 513.530s
- sectionSection 9tts000001-0002.mp3 · 687.880s
- sectionSection 10tts000001-0002.mp3 · 786.420s
- chapterArticle IItts000001-0003.mp3 · 0.500s
- sectionSection 1tts000001-0003.mp3 · 2.780s
- sectionSection 2tts000001-0003.mp3 · 233.810s
- sectionSection 3tts000001-0003.mp3 · 314.500s
- sectionSection 4tts000001-0003.mp3 · 351.450s
- chapterArticle IIItts000001-0004.mp3 · 0.500s
- sectionSection 1tts000001-0004.mp3 · 2.830s
- sectionSection 2tts000001-0004.mp3 · 31.970s
- sectionSection 3tts000001-0004.mp3 · 119.620s
- chapterArticle IVtts000001-0005.mp3 · 0.500s
- sectionSection 1tts000001-0005.mp3 · 2.810s
- sectionSection 2tts000001-0005.mp3 · 22.230s
- sectionSection 3tts000001-0005.mp3 · 68.890s
- sectionSection 4tts000001-0005.mp3 · 111.010s
- chapterArticle Vtts000001-0006.mp3 · 0.500s
- chapterArticle VItts000001-0007.mp3 · 0.500s
- chapterArticle VIItts000001-0008.mp3 · 0.500s
- closeEnd of The Constitution of the United States of America, 1787tts000001-0008.mp3 · 109.590s
Validation
| ✓ | File names are lower case | |
| ✓ | No more than 250 files | 17 files |
| ✓ | Audio sequence starts at -0001 and is continuous | 8 primary audio files |
| ✓ | tts000001.opf present | |
| ✓ | tts000001.ncx present | |
| ✓ | tts000001.smil present | |
| ✓ | tts000001hdgs.mp3 present | |
| ✓ | tts000001dtb.md5 present | |
| ✓ | tts000001.opf is valid to its DTD (offline) | |
| ✓ | tts000001.ncx is valid to its DTD (offline) | |
| ✓ | tts000001.smil is valid to its DTD (offline) | |
| ✓ | tts000001dtb.md5 is valid to its DTD (offline) | |
| ✓ | navPoint playOrder runs 1..n in document order | 31 navPoints |
| ✓ | No more than 5,000 navPoints | |
| ✓ | navPoint classes come from Spec 1203 Table 1 | |
| ✓ | Every navPoint points to a SMIL element | |
| ✓ | Every navLabel has text and audio | |
| ✓ | dtb:depth matches the navPoint nesting | declared 2 |
| ✓ | Every SMIL audio has clipBegin before clipEnd | 170 clips |
| ✓ | SMIL file is at most 100 KiB | 21.6 KiB |
| ✓ | Every audio src exists | |
| ✓ | dc:Identifier has id=uid and matches NCX and SMIL | sample-tts000001 |
| ✓ | dtb:multimediaType is audioNCX | |
| ✓ | dtb:totalTime equals the summed SMIL audio within 1 s | 0:27:27.950 vs 1648.0 s |
| ✓ | Manifest lists every file except the checksum file | |
| ✓ | dc:Date is yyyy-mm | |
| ✓ | Checksum file matches every file | 16 files |
| ✓ | Checksum <book> matches the dc:Identifier | |
| ✓ | Clip timing within Spec 1203 windows (measured) | 203/203 clips |
| ✓ | MP3 duration within 0.1 s of its master | max drift 0.000 s |
Intelligibility
Each track was transcribed with whisper.cpp ggml-small.en.bin and compared with the text the voice was given. Lower is clearer; most remaining differences are numbers written as digits, words that sound alike (marque, mark), 1787 spellings and signers' names.
| tts000001-0001.mp3 | 73 words, 2.7% WER | |
| tts000001-0002.mp3 | 2270 words, 0.8% WER | |
| tts000001-0003.mp3 | 1025 words, 0.4% WER | |
| tts000001-0004.mp3 | 377 words, 0.0% WER | |
| tts000001-0005.mp3 | 330 words, 0.0% WER | |
| tts000001-0006.mp3 | 145 words, 3.5% WER | |
| tts000001-0007.mp3 | 156 words, 1.3% WER | |
| tts000001-0008.mp3 | 199 words, 12.6% WER |
Pronunciation lexicon
Rules applied before synthesis, each logged for review. They fix the abbreviations in the signers' names.
| Text | Spoken as |
|---|---|
| chuse | choose |
| — | , |
| Go. WASHINGTON— Presid. | George Washington, President, |
| Wm. | William |
| Saml. | Samuel |
| Wil: | William |
| Jona: | Jonathan |
| B Franklin | Benjamin Franklin |
| Geo. | George |
| Robt | Robert |
| Thos | Thomas |
| Gouv | Gouverneur |
| Jaco: | Jacob |
| Geo: | George |
| jun | junior |
| Dan of St Thos. Jenifer | Daniel of Saint Thomas Jenifer |
| Danl | Daniel |
| Mchenry | McHenry |
| Jr. | Junior |
| Rich'd | Richard |
| Hu | Hugh |
| J. Rutledge | John Rutledge |
| Abr | Abraham |