VOB Splitter: Fast Ways to Split VOB Files Without Quality Loss

VOB Splitter Tutorial: Split, Convert, and Preserve SubtitlesVOB (Video Object) files are the container format used on DVDs to store video, audio, subtitles, and navigation data. Because VOB bundles multiple streams together and often contains long recordings (movies, concerts, TV rips), you may need to split a VOB file into smaller segments — for easier editing, uploading, burning to new discs, or extracting specific scenes. This tutorial shows practical, step-by-step methods to split VOB files, convert them to modern formats, and preserve subtitle tracks throughout the process.

---

When and why to split VOB files

• Splitting makes large DVD rips manageable for editing or upload size limits.
• Extracting scenes saves time when you only need a portion of a recording.
• Some players and tools handle shorter files or standard container formats (MP4, MKV) more reliably.
• Converting while splitting lets you move from DVD-era codecs to more efficient modern codecs (H.264/H.265) and containers that better support subtitles.

---

Tools you can use (cross-platform options)

• HandBrake — free, GUI, excellent for conversion (MP4/MKV) and subtitle handling.
• FFmpeg — free, command-line, highly flexible for splitting, converting, remuxing, and preserving streams.
• MKVToolNix / mkvmerge — great for remuxing into MKV while keeping subtitles, chapters, and multiple audio tracks intact.
• Avidemux — simple GUI tool for cutting video without re-encoding (when container/codecs permit).
• DVD Decrypter / MakeMKV — useful when first extracting VOBs from encrypted DVDs (MakeMKV outputs MKV directly).

---

Key concepts before you start

• Splitting by remuxing keeps original video/audio (no quality loss) but requires compatible containers. Remuxing moves streams into another container without re-encoding.
• Re-encoding lets you change codec, resolution, or bitrate (useful for reducing size), but it takes more time and can reduce quality if settings are too low.
• Subtitles come in two main forms on DVDs: VobSub (image-based bitmap subtitles) and closed captions. VobSub consists of .sub (bitmap data) and .idx (timing/index) if extracted. Converting to text-based subtitles (SRT) requires OCR (e.g., Subtitle Edit, OCR tools) and sometimes manual correction.
• Timecodes and frame accuracy matter if you need precise cuts; tools like FFmpeg and Avidemux can cut on GOP boundaries or perform frame-accurate re-encodes.

---

1) Splitting VOB files using FFmpeg (remuxing without quality loss)

This method copies streams into new files without re-encoding (fast, lossless), if your target container supports the streams.

Basic command to split by duration (e.g., 10-minute segments):

ffmpeg -i input.vob -c copy -map 0 -f segment -segment_time 600 -reset_timestamps 1 out%03d.vob 

• -c copy copies all streams (video, audio, subtitles) without re-encoding.
• -map 0 includes all streams from the input.
• -f segment and -segment_time split by length (seconds).
• reset_timestamps helps with playback in some players.

Notes:

• Many players expect VOBs to be in a DVD-compatible structure (VIDEO_TS), so segmented VOBs may play differently. Consider remuxing to MKV or MP4 instead.

To split and remux into MKV segments while preserving subtitles:

ffmpeg -i input.vob -c copy -map 0 -f segment -segment_time 600 -reset_timestamps 1 out%03d.mkv 

MKV is recommended because it supports multiple audio tracks and subtitle types cleanly.

To split between specific timestamps (e.g., extract 00:10:00–00:20:00):

ffmpeg -ss 00:10:00 -to 00:20:00 -i input.vob -c copy clip.mkv 

Place -ss before -i for fast seeking (less accurate on some formats) or after -i for frame-accurate seeking (slower).

---

2) Frame-accurate cutting (re-encode or smart copy)

If you need exact frame cuts and cannot accept GOP-boundary cuts, re-encoding is required or use tools that support frame-accurate copy.

FFmpeg re-encode example (H.264, preserve subtitles by copying VobSub or converting):

ffmpeg -ss 00:10:00 -to 00:20:00 -i input.vob -c:v libx264 -crf 18 -preset medium -c:a aac -b:a 192k -c:s copy clip.mkv 

• -c:v libx264 re-encodes video with quality controlled by -crf (lower = better).
• -c:s copy copies subtitle streams if they’re compatible with MKV.

If subtitle streams are VobSub and you want them burned into the video (hard subtitles):

ffmpeg -ss 00:10:00 -to 00:20:00 -i input.vob -vf "subtitles=input.vob" -c:v libx264 -crf 18 -c:a aac clip_hardsub.mp4 

• Hardcoding subtitles embeds them into the picture; they cannot be turned off.

---

3) Preserve VobSub subtitles or convert to text-based SRT

• To keep VobSub (.sub/.idx) with streams when remuxing, ensure the target container supports them (MKV does). Using mkvmerge is straightforward:

  mkvmerge -o output.mkv input.vob 

  This will extract and include VobSub tracks in the MKV.

• To extract VobSub from VOB into separate .sub/.idx: Use subtitler tools like Subtitle Edit (GUI) or FFmpeg’s subtitle extraction (FFmpeg can dump subtitles into .sub/.idx in some cases), but a reliable GUI approach:

  1. Open the VOB in Subtitle Edit.
  2. Export -> Export as VobSub (.sub/.idx) or to text via OCR (requires Tesseract).
  3. Clean OCR errors manually.

• Convert VobSub to SRT via OCR:

  • Use Subtitle Edit or BDSup2Sub + OCR tools.
  • OCR is imperfect; expect manual corrections, especially with stylized fonts, low resolution, or non-English text.

Example workflow with Subtitle Edit:

1. Open VOB -> File -> Open video or load DVD folder.
2. Tools -> VobSub (Load .sub/.idx) or directly “Import VobSub”.
3. Use “OCR” to convert images to text and export as SRT.
4. Save and verify timings.

---

4) Using HandBrake (GUI) to convert and keep subtitle support

HandBrake is user-friendly for converting VOB/DVD rips to MP4/MKV and supports subtitles.

Steps:

1. Open HandBrake and load input VOB or DVD folder.
2. Select a preset (e.g., “Fast 1080p30” or “HQ 720p30”).
3. In “Summary,” choose container MKV if you want to keep VobSub; MP4 may not support image-based subtitles.
4. In “Subtitles,” add the subtitle track — choose “Burn In” to hardcode, “Foreign Audio Search” for auto-detect, or just add as a selectable track if available.
5. Set video settings (codec, quality CRF or bitrate).
6. Start Encode.

Notes:

• HandBrake will re-encode video/audio. To avoid re-encoding, use remuxing tools (FFmpeg/mkvmerge), but HandBrake is simpler for conversion and subtitle handling.

---

5) Batch splitting and automation

For many files, script FFmpeg commands or use a GUI batch tool.

Example simple bash loop to split multiple VOBs into 10-minute MKV segments:

for f in *.vob; do   ffmpeg -i "$f" -c copy -map 0 -f segment -segment_time 600 -reset_timestamps 1 "${f%.*}_part%03d.mkv" done 

Windows PowerShell equivalent uses similar FFmpeg calls with a foreach loop.

---

6) Common problems and solutions

• Broken subtitle timings after remux: Use -reset_timestamps 1 or remux carefully with mkvmerge.
• Players not seeing subtitle tracks: Use MKV at best; MP4 may not carry VobSub. Or convert VobSub to SRT.
• Poor OCR results: Improve source resolution (upscale temporarily for OCR), tweak OCR language settings, or correct manually.
• Sync drift after cutting: Prefer re-encoding with -ss after -i for accurate cuts, or use timestamps carefully.

---

Quick practical example — Extract a scene, convert to MP4, keep SRT subtitles

1. Extract VobSub and OCR to SRT with Subtitle Edit (clean the SRT).
2. Use FFmpeg to create a frame-accurate, re-encoded MP4 with the SRT added:

   
   ffmpeg -ss 00:10:00 -to 00:20:00 -i input.vob -i subs.srt -c:v libx264 -crf 18 -preset medium -c:a aac -b:a 192k -c:s mov_text -map 0:v -map 0:a -map 1:0 output_clip.mp4 

• -c:s mov_text converts SRT into MP4-friendly subtitle format.
• -map entries ensure streams are mapped correctly.

---

Recommendations

• For lossless splitting with subtitle preservation, remux to MKV using FFmpeg or mkvmerge. MKV preserves audio and VobSub subtitles reliably.
• For distribution to players/devices or smaller files, convert to MP4/H.264 or H.265, and convert subtitles to SRT (soft) or burn them (hard) if necessary.
• Use Subtitle Edit for VobSub extraction and OCR; review and correct the resulting SRT before distribution.

---

If you want, tell me:

• The platform you’re on (Windows/macOS/Linux), and
• Whether you prefer GUI tools or command line, and
  I’ll give a tailored step-by-step with exact commands for your setup.