How do I re-encode MP4 to VOB without quality loss?
+
Upload the MP4 file and our converter applies a CRF-based re-encode targeting visually-lossless VOB output (CRF 18 by default, lower = larger / higher quality). The codec is chosen to match the VOB container — H.264 / H.265 / VP9 / AV1 as appropriate.
Which codec does the VOB output use?
+
It depends on the container. MP4 defaults to H.264 (broadest playback support); MKV defaults to H.265 for ~50% smaller file at the same quality; WebM defaults to VP9 or AV1 (royalty-free web streaming). You can override the codec choice in the advanced options before VOB conversion runs.
Will my audio track survive MP4 to VOB?
+
Yes — audio is re-muxed when MP4 and VOB share an audio codec, or re-encoded to AAC / Opus / Vorbis depending on what the VOB container supports. Multi-track audio (commentary, alternate languages) is preserved in containers that support it (MKV, WebM, MP4).
Can I keep the original framerate going from MP4 to VOB?
+
By default framerate is unchanged (MP4 24fps stays 24fps in VOB). If you need to change it (e.g. interlaced 29.97 to progressive 30fps) the framerate option handles 3:2 pulldown and deinterlacing in the same pass — no second decode required.
What is the file size difference between MP4 and VOB?
+
Same-codec re-muxes (H.264 in both MP4 and VOB) produce nearly-identical sizes. Codec changes can swing things dramatically: H.264 -> H.265 typically halves the file at the same visual quality; H.264 -> VP9 is roughly comparable; AV1 is currently the smallest at the cost of slower encode time.
Will the VOB file play on iPhone / Android / Smart TV?
+
MP4 / H.264 plays everywhere natively. MOV / H.264 plays on Apple devices and most Smart TVs but not on older Android. MKV needs VLC on iOS. WebM plays in browsers but not most Smart TV apps. The "device compatibility" preset in advanced options picks the safest codec / container for your target.
How long does converting a 1-hour MP4 file to VOB take?
+
Depends on the codec change. Same-codec re-mux: 30-60 seconds (no re-encode). Re-encode to a different codec: typically 0.3-0.7x source duration on our GPU pipeline, so a 1-hour MP4 -> VOB finishes in 18-40 minutes; AV1 re-encodes are 2-3x slower.
What is the max resolution supported for MP4 to VOB?
+
Up to 8K (7680x4320) on Pro. Free is capped at 4K per the file-size limit. HDR metadata (HDR10, Dolby Vision) is preserved where both MP4 and VOB containers and codecs support it; SDR sources stay SDR.
Is my MP4 video private during VOB conversion?
+
Yes — uploaded video files are processed in isolated workers and deleted within minutes of completion. No human review, no retention beyond the documented window. See /privacy/.
Can I crop or trim during the MP4 to VOB step?
+
Not in the same step — use /video-trim/ or /video-cutter/ to clip the MP4 first, then queue the MP4 -> VOB conversion. Trim-then-convert is faster than re-encoding the whole file just to crop the output.
Why is the VOB file blurry compared to the MP4 source?
+
Almost always a bitrate-too-low setting. Re-encoding a high-bitrate MP4 into a lower-bitrate VOB at the default CRF compresses motion-heavy scenes heavily. Push CRF down to 16-18 (or set an explicit bitrate ceiling) and re-run to recover quality.
Does the MP4 to VOB converter support subtitles?
+
Yes — embedded subtitle tracks (mov_text in MP4, SRT / ASS in MKV, WebVTT in WebM) are preserved when both MP4 and VOB containers support them. Burned-in (hardsub) subtitles transfer automatically because they are part of the pixel data.