Sobre os arquivos Y4M
YUV4MPEG2
Formato raw uncompressed video (YUV) com headers texto. Usado em testes de codec, pesquisa de compressão, pipelines técnicos. Arquivos enormes.
Família
Video Files
Extensão
.y4m
Tipo MIME
video/x-raw-yuv
Pode ser usado como
COMO NASCEU O
FORMATO Y4M.
Y4M — YUV4MPEG2 — is a raw uncompressed video container used almost exclusively by codec developers. The format is brutally simple: a one-line ASCII header (`YUV4MPEG2 W1920 H1080 F30:1 Ip A1:1 C420 XCS=100`), then alternating frames prefixed with `FRAME\n` markers, then raw YUV pixel data. No compression, no timecodes beyond the framerate — a video codec’s perfect ground-truth input.
X264, x265, SVT-AV1, every video codec encoder on Earth accepts .y4m as test input. A 10-second 1080p Y4M weighs 600 MB uncompressed, which is the entire point: no prior codec decisions have been baked in, so codec-quality comparisons use Y4M as the source of truth.
CURIOSIDADES E
FATOS INTERESSANTES.
Every video codec benchmark on the planet uses Y4M as ground-truth source — x264, x265, AOM AV1, SVT-AV1.
Y4M's header is one ASCII line — trivially parseable and human-readable.
10 seconds of 1080p Y4M is about 600 MB — codec developers work with terabytes of Y4M test data.
The `FRAME\n` marker between frames is deliberately simple — parsers can seek by scanning.
Y4M's simplicity is why codec papers always cite Y4M inputs: no ambiguity about pre-processing.
VANTAGENS E
LIMITAÇÕES.
Vantagens
- Uncompressed raw YUV — codec benchmark truth.
- Dead-simple header.
- Universal codec development support.
Limitações
- Enormous file sizes.
- Development-only — not for consumption.
- No metadata beyond basic stream params.
Tamanhos típicos de arquivo
10 sec 1080p Y4M
~600 MB
1 min 4K Y4M
~14 GB
Especificações técnicas
- MIME type
- video/x-yuv4mpeg2
- Extension
- .y4m
- Pixel format
- YUV 4:2:0, 4:2:2, 4:4:4
- Header
- ASCII single line
CONVERTER A PARTIR DE
Y4M
Casos de uso comuns
Video quality benchmarking, uncompressed intermediate, codec testing
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Conversões populares de Y4M
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Perguntas frequentes sobre Y4M
Perguntas frequentes
Y4M (YUV4MPEG2) is a video container formato that bundles one ou more video streams, audio tracks, e optional subtitles em a single file. The container formato determines how metadata is organised e which codecs can live inside; the visual quality itself depende de the codec (H.264, H.265, VP9, AV1) em vez de the Y4M wrapper. It is part of the video arquivos family.
VLC, MPV e PotPlayer reproduzir nearly every Y4M arquivo on desktop. Browser support varies: moderno Chromium, Firefox e Safari reproduzir common containers via the HTML5 <video> tag, mas niche Y4M variants may fail. If a device refuses your Y4M, converter to MP4 com our Y4M to MP4 converter para universal playback.
Upload your Y4M to KaijuConverter e pick MP4, MOV, MKV, WebM, ou any other target. Our pipeline uses FFmpeg under the hood e stream-copies when codecs are compatível (no quality loss) ou transcodes at alta-quality defaults otherwise. Conversion runs server-side; both arquivos delete within two hours.
Only when the target requires re-encoding. If the codecs inside Y4M match what the target container supports, FFmpeg stream-copies the streams e the output is bit-identical para o source. Transcoding uses transparente quality defaults (CRF 20–23 H.264) e produces output indistinguishable de the original at normal viewing distance.