VideOCR timminator

Tips

When cropping, leave a bit of buffer space above and below the text to ensure accurate readings, but also don't make the box to large.

Quick Configuration Cheatsheet

Command Line Parameters (CLI version)

• video_path

  Path for the video where subtitles should be extracted from.

• output

  Path for the desired location where the .srt file should be stored.

• lang

  The language of the subtitles. See PaddleOCR docs for list of supported languages and their abbreviations.

• subtitle_position

  Specifies the alignment of subtitles in the video and allows for better text recognition.

• conf_threshold

  Confidence threshold for word predictions. Words with lower confidence than this value will be discarded. The default value 75 is fine for most cases.

  Make it closer to 0 if you get too few words in each line, or make it closer to 100 if there are too many excess words in each line.

• sim_threshold

  Similarity threshold for subtitle lines. Subtitle lines with larger Levenshtein ratios than this threshold will be merged together. The default value 80 is fine for most cases.

  Make it closer to 0 if you get too many duplicated subtitle lines, or make it closer to 100 if you get too few subtitle lines.

• ssim_threshold

  If the SSIM between consecutive frames exceeds this threshold, the frame is considered similar and skipped for OCR. A lower value can greatly reduce the number of images OCR needs to be performed on. On relatively tight crop boxes around the subtitle area good results could be seen with this value all the way lowered to 85.

• post_processing

  This parameter adds a post processing step to the subtitle detection. The detected text will be analyzed for missing spaces (as this is a common issue with PaddleOCR) and tries to insert them automatically. Currently only available for English, Spanish, Portuguese, German, Italian and French. For more info check out my wordninja-enhanced repository.

• max_merge_gap

  Maximum allowed time gap (in seconds) between two subtitles to be considered for merging if they are similar. The default value 0.09 (i.e., 90 milliseconds) works well in most scenarios.

  Increase this value if you notice that the output SRT file contains several subtitles with the same text that should be merged into a single one and are wrongly split into multiple ones. This can happen if the PaddleOCR OCR engine is not able to detect any text for a short amount of time while the subtitle is displayed in the selected video.

• time_start and time_end

  Extract subtitles from only a clip of the video. The subtitle timestamps are still calculated according to the full video length.

• use_fullframe

  By default, the specified cropped area is used for OCR or if a crop is not specified, then the bottom third of the frame will be used. By setting this value to True the entire frame will be used.

• use_dual_zone

  This parameter allows two specify two areas that will be used for OCR.

• crop_x(2), crop_y(2), crop_width(2), crop_height(2)

  Specifies the bounding area(s) in pixels for the portion of the frame that will be used for OCR. See image below for example:

• use_gpu

  Set to True if performing OCR with GPU.

• use_angle_cls

  Set to True if classification should be enabled.

• brightness_threshold

  If set, pixels whose brightness are less than the threshold will be blackened out. Valid brightness values range from 0 (black) to 255 (white). This can help improve accuracy when performing OCR on videos with white subtitles.

• frames_to_skip

  The number of frames to skip before sampling a frame for OCR. Keep in mind the fps of the input video before increasing.

• min_subtitle_duration

  Subtitles shorter than this threshold will be omitted from the final subtitle file.

• use_server_model

  By default the smaller model are used for the OCR process. This parameter enables the usage of the server models for OCR. This can result in better text detection at the cost of more processing power. Should only ever be used in the GPU version.