CONVERT H264 → MP4 (H264 to MP4)
Fast, secure H264 to MP4 conversion. No registration required.
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HOW TO CONVERT H264 → MP4
Drop the video file
Select a H264 file. We read the container and stream descriptors to plan the conversion.
FFmpeg handles the repackage
When codecs align, FFmpeg rewraps the existing streams into a MP4 container — no quality loss, near-instant finish.
Retrieve the MP4
The MP4 download is ready in seconds for stream-copy jobs, minutes for full transcodes.
H264 is a video container, so playback depends on the codec inside as well as the wrapper itself. Reaching a MP4 from there is one hop. If you need a MP4 version of a H264 clip for a social platform, a stock site or a CMS upload widget, this tool handles the job without re-rendering anything when it does not have to. The output is the same pixel data in a container the destination actually accepts. One more beat. H264 is a video container, so playback depends on the codec inside as well as the wrapper itself. Receiving format: MP4 is the MPEG-4 Part 14 container, the web's default video format with H.264/H.265 support.
Why convert H264 to MP4
Sending H264 to someone on a non-matching operating system frequently leads to "file cannot be opened". MP4 avoids that by sitting in the middle of everyone's compatibility list. The repackage runs quickly and without generational loss when codecs already align.
H264 vs MP4 — Technical specifications
Side-by-side comparison of the technical details.
H264
- MIME type
- video/h264
- Extensions
- .h264, .264, .avc (raw bytestream)
- Standard
- ITU-T Rec. H.264 / ISO/IEC 14496-10 (AVC)
- Typical containers
- MP4, MKV, MOV, TS, FLV
- Profiles
- Baseline, Main, High, High 10, High 4:2:2, High 4:4:4
- MIME Type
- video/h264
- Extension
- .h264
- Category
- Video Files
- Full Name
- H.264 Raw Stream
- Conversion Engine
- FFMPEG
MP4
- MIME type
- video/mp4
- MIME Type
- video/mp4
- Extension
- .mp4
- Category
- Video Files
- Full Name
- MP4 Video
- Conversion Engine
- FFMPEG
- Container
- ISO Base Media File Format (ISO/IEC 14496-12)
- Common video codecs
- H.264 (AVC), H.265 (HEVC), AV1, VP9
- Common audio codecs
- AAC, MP3, FLAC, Opus
- Max file size
- Practically ~16 TB; 2^63 bytes theoretical
- Streaming
- Supported with faststart (moov atom at front)
| Specification | H264 | MP4 |
|---|---|---|
| MIME type | video/h264 | video/mp4 |
| Extensions | .h264, .264, .avc (raw bytestream) | — |
| Standard | ITU-T Rec. H.264 / ISO/IEC 14496-10 (AVC) | — |
| Typical containers | MP4, MKV, MOV, TS, FLV | — |
| Profiles | Baseline, Main, High, High 10, High 4:2:2, High 4:4:4 | — |
| MIME Type | video/h264 | video/mp4 |
| Extension | .h264 | .mp4 |
| Category | Video Files | Video Files |
| Full Name | H.264 Raw Stream | MP4 Video |
| Conversion Engine | FFMPEG | FFMPEG |
| Container | — | ISO Base Media File Format (ISO/IEC 14496-12) |
| Common video codecs | — | H.264 (AVC), H.265 (HEVC), AV1, VP9 |
| Common audio codecs | — | AAC, MP3, FLAC, Opus |
| Max file size | — | Practically ~16 TB; 2^63 bytes theoretical |
| Streaming | — | Supported with faststart (moov atom at front) |
H264 vs MP4 — Strengths and limitations
What each format does best, and where it falls short.
H264 Strengths
- Universal hardware decode on every device since ~2010.
- 40-50% smaller than MPEG-2 at equal quality.
- Mature ecosystem with dozens of encoders (x264 is the open-source gold standard).
- Every browser, phone, TV, and car infotainment supports H.264.
- Supports everything from 144p vertical phone video to 8K HDR masters.
Limitations
- Patent-encumbered — encoding royalties apply for commercial use.
- 30-50% larger than H.265/AV1 at equivalent quality.
- Raw .h264 bytestreams have no timecode — containers (MP4/MKV) add that.
MP4 Strengths
- Universal playback — every browser, phone, TV, game console, and editing suite reads MP4.
- Supports modern codecs (H.264, H.265, AV1) with no container changes.
- Progressive streaming works with the "moov atom" at the start of the file.
- Carries subtitles, chapters, multiple audio tracks, and embedded metadata.
- ISO-standardized (ISO/IEC 14496-14) and patent-licensable via MPEG LA.
Limitations
- Codec licensing (H.264, H.265) carries royalty costs for commercial use.
- Streaming requires the moov atom at the start — a misplaced atom breaks web playback.
- Not ideal for lossless or professional editing workflows (use ProRes or DNxHD instead).
Quality & Compatibility
Resolution, frame rate and colour space are preserved end-to-end. If the MP4 container does not support some H264 features (chapters, multiple subtitle tracks, DRM-protected streams), those are flattened or dropped with a warning. Hard-coded subtitles in the video frames always survive.
Tips for Best Results
- Embedded subtitle tracks convert between H264 and MP4 when both containers support the same subtitle codec; otherwise burn the subtitles into the video first.
- For portrait (9:16) clips, make sure the MP4 encoder preserves the correct display aspect ratio — some players default to 16:9 if SAR is ambiguous.
- Long recordings (over an hour) benefit from chapter metadata; MP4 may not preserve H264 chapters — check before relying on them.
Frequently Asked Questions
Only when it has to. If the codecs inside H264 (usually H.264 or H.265 for video, AAC for audio) are accepted by MP4, we stream-copy — the bytes are repackaged into the new container with zero re-encoding and no quality loss. When the source uses a codec the target does not support, we transcode at a matching bitrate to keep the visual quality close to the original.
With stream copy, expect the job to finish in seconds to tens of seconds regardless of video length — the work is mostly rewriting the container. Transcoding is slower (roughly real-time: a ten-minute clip takes about ten minutes) because every frame must be decoded and re-encoded. The progress bar shows which mode applies.
Yes. Resolution, frame rate, colour space and bit depth are preserved by default; stream copy is literally bit-identical on these parameters. If you explicitly pick a lower bitrate or a different codec in Advanced, the output is rebuilt to those settings, but the default is always "match the source".
H.264 Raw Stream
Source formatH.264 raw stream is an elementary bitstream containing only the video data encoded with the H.264/AVC codec without any container. It is commonly used as an intermediate format in video processing pipelines and for hardware encoder output.
MP4 Video
Target formatMP4 is the most universally supported video container format. It typically uses H.264 or H.265 video codecs with AAC audio, providing an excellent balance of quality and file size across all devices and platforms.
Common Use Cases
Share across platforms
Send MP4 files to anyone without worrying about whether they have the right software for H264.
Embed in documents
Drop MP4 output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
MP4 often produces smaller files than H264 for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
H264 vs MP4 — Typical file sizes
Approximate file sizes for common scenarios.
- 1080p 30fps @ 5 Mbps (1 min) ~37 MB
- 4K 60fps @ 35 Mbps (1 min) ~260 MB
- HD streaming (1 hour, 6 Mbps) ~2.7 GB
- Smartphone video (1080p, 1 min) 60–120 MB
- 4K video (1 min, H.265) 200–400 MB
- Streamed movie (90 min, H.264) 1–4 GB
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Related comparisons
See these formats side by side to understand which fits your use case best.
Related Guides
MP4 Container Format: The Universal Video Standard
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