diff --git a/README.md b/README.md
index e116f2a..967ec80 100644
--- a/README.md
+++ b/README.md
@@ -1,16 +1,18 @@
# videocr
-
+Extract hardcoded subtitles from videos using the [Tesseract](https://github.com/tesseract-ocr/tesseract) OCR engine with Python.
-
+Input video with hardcoded subtitles:
-
+
+
+
+
-```
+```python
import videocr
print(videocr.get_subtitles('video.avi', lang='HanS'))
-
```
Output:
@@ -46,3 +48,47 @@ Un, I'll have a vodka tonic.
Laughs Thanks.
```
+
+## API
+
+```python
+videocr.get_subtitles(
+ video_path: str, lang='eng', time_start='0:00', time_end='',
+ conf_threshold=65, sim_threshold=90, use_fullframe=False)
+```
+Return the subtitles string in SRT format.
+
+
+```python
+
+videocr.save_subtitles_to_file(
+ video_path: str, file_path='subtitle.srt', lang='eng', time_start='0:00',
+ time_end='', conf_threshold=65, sim_threshold=90, use_fullframe=False)
+```
+Write subtitles to `file_path`. If the file does not exist, it will be created automatically.
+
+## Adjustable Parameters
+
+- `lang`
+
+ Language of the subtitles in the video.
+
+- `time_start` and `time_end`
+
+ Extract subtitles from only a part of the video. The subtitle timestamps are still calculated according to the full video length.
+
+- `conf_threshold`
+
+ Confidence threshold for word predictions. Words with lower confidence than this threshold are discarded. The default value is fine for most cases.
+
+ Make it closer to 0 if you get too few words from the predictions, or make it closer to 100 if you get too many excess words.
+
+- `sim_threshold`
+
+ Similarity threshold for subtitle lines. Neighbouring subtitles with larger [Levenshtein](https://en.wikipedia.org/wiki/Levenshtein_distance) ratios than this threshold will be merged together. The default value is fine for most cases.
+
+ Make it closer to 0 if you get too few subtitle lines, or make it closer to 100 if you get too many duplicated subtitles.
+
+- `use_fullframe`
+
+ By default, only the bottom half of each frame is used for OCR in order to reduce errors. You can explicitly make the algorithm handle the full frame.