NUT


Table of Contents


1 Description

NUT is a low overhead generic container format. It stores audio, video, subtitle and user-defined streams in a simple, yet efficient, way.

It was created by a group of FFmpeg and MPlayer developers in 2003 and was finalized in 2008.

The official nut specification is at svn://svn.mplayerhq.hu/nut In case of any differences between this text and the official specification, the official specification shall prevail.

2 Modes

NUT has some variants signaled by using the flags field in its main header.

BROADCASTExtend the syncpoint to report the sender wallclock
PIPEOmit completely the syncpoint

2.1 BROADCAST

The BROADCAST variant provides a secondary time reference to facilitate detecting endpoint latency and network delays. It assumes all the endpoint clocks are synchronized. To be used in real-time scenarios.

2.2 PIPE

The PIPE variant assumes NUT is used as non-seekable intermediate container, by not using syncpoint removes unneeded overhead and reduces the overall memory usage.

3 Container-specific codec tags

3.1 Generic raw YUVA formats

Since many exotic planar YUVA pixel formats are not considered by the AVI/QuickTime FourCC lists, the following scheme is adopted for representing them.

The first two bytes can contain the values: Y1 = only Y Y2 = Y+A Y3 = YUV Y4 = YUVA

The third byte represents the width and height chroma subsampling values for the UV planes, that is the amount to shift the luma width/height right to find the chroma width/height.

The fourth byte is the number of bits used (8, 16, ...).

If the order of bytes is inverted, that means that each component has to be read big-endian.

3.2 Raw Audio

ALAWA-LAW
ULAWMU-LAW
P<type><interleaving><bits>little-endian PCM
<bits><interleaving><type>Pbig-endian PCM

<type> is S for signed integer, U for unsigned integer, F for IEEE float <interleaving> is D for default, P is for planar. <bits> is 8/16/24/32

PFD[32]   would for example be signed 32 bit little-endian IEEE float

3.3 Subtitles

UTF8Raw UTF-8
SSA[0]SubStation Alpha
DVDSDVD subtitles
DVBSDVB subtitles

3.4 Raw Data

UTF8Raw UTF-8

3.5 Codecs

3IV1non-compliant MPEG-4 generated by old 3ivx
ASV1Asus Video
ASV2Asus Video 2
CVIDCinepak
CYUVCreative YUV
DIVXnon-compliant MPEG-4 generated by old DivX
DUCKTruemotion 1
FFV1FFmpeg video 1
FFVHFFmpeg Huffyuv
H261ITU H.261
H262ITU H.262
H263ITU H.263
H264ITU H.264
HFYUHuffyuv
I263Intel H.263
IV31Indeo 3.1
IV32Indeo 3.2
IV50Indeo 5.0
LJPGITU JPEG (lossless)
MJLSITU JPEG-LS
MJPGITU JPEG
MPG4MS MPEG-4v1 (not ISO MPEG-4)
MP42MS MPEG-4v2
MP43MS MPEG-4v3
MP4VISO MPEG-4 Part 2 Video (from old encoders)
mpg1ISO MPEG-1 Video
mpg2ISO MPEG-2 Video
MRLEMS RLE
MSVCMS Video 1
RT21Indeo 2.1
RV10RealVideo 1.0
RV20RealVideo 2.0
RV30RealVideo 3.0
RV40RealVideo 4.0
SNOWFFmpeg Snow
SVQ1Sorenson Video 1
SVQ3Sorenson Video 3
theoXiph Theora
TM20Truemotion 2.0
UMP4non-compliant MPEG-4 generated by UB Video MPEG-4
VCR1ATI VCR1
VP30VP 3.0
VP31VP 3.1
VP50VP 5.0
VP60VP 6.0
VP61VP 6.1
VP62VP 6.2
VP70VP 7.0
WMV1MS WMV7
WMV2MS WMV8
WMV3MS WMV9
WV1Fnon-compliant MPEG-4 generated by ?
WVC1VC-1
XVIDnon-compliant MPEG-4 generated by old Xvid
XVIXnon-compliant MPEG-4 generated by old Xvid with interlacing bug