7.1. Video codecs
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## 7.1. Video codecs

The codec status table is a complete list of all supported codecs, regenerated daily. Some binary codecs for use with MPlayer are available in the download section of our homepage.

The most important ones above all:

- MPEG-1 (VCD) and MPEG-2 (DVD) video

- native decoders for all DivX variants, 3ivX, M$ MPEG-4 v1, v2 and other MPEG-4 variants

- native decoder for Windows Media Video 7/8 (WMV1/WMV2), and Win32 DLL decoder for Windows Media Video 9 (WMV3), both used in `.wmv` files

- native Sorenson 1 (SVQ1) decoder

- native Sorenson 3 (SVQ3) decoder

- 3ivx v1, v2 decoder

- Cinepak and Intel Indeo codecs (3.1,3.2,4.1,5.0)

- MJPEG, AVID, VCR2, ASV2 and other hardware formats

- VIVO 1.0, 2.0, I263 and other H.263(+) variants

- FLI/FLC

- RealVideo 1.0 & 2.0 from `libavcodec`, and RealVideo 3.0 & 4.0 codecs using RealPlayer libraries

- native decoder for HuffYUV

- Various old simple RLE-like formats

If you have a Win32 codec not listed here which is not supported yet, please read the codec importing HOWTO and help us add support for it.

### 7.1.1. FFmpeg/libavcodec

FFmpeg contains `libavcodec`, the leading open source video and audio codec library. It is capable of decoding most multimedia formats, usually at higher speeds than the alternatives, and aims to add support for the rest of them eventually. It is the default decoder for the majority of codecs that MPlayer supports. Encoding is also possible for some formats and supported in MEncoder.

For a complete list of supported video and audio codecs please visit the FFmpeg homepage.

MPlayer contains `libavcodec`. Just run `./configure` and compile.

### 7.1.2. Xvid

Xvid is a free software MPEG-4 ASP compliant video codec, which features two pass encoding and full MPEG-4 ASP support, making it a lot more efficient than the well-known DivX codec. It yields very good video quality and good performance due to CPU optimizations for most modern processors.

It began as a forked development of the OpenDivX codec. This happened when ProjectMayo changed OpenDivX to closed source DivX4, and the non-ProjectMayo people working on OpenDivX got angry, then started Xvid. So both projects have the same origin.

Note that Xvid is not necessary to decode Xvid-encoded video. `libavcodec` is used by default as it offers better speed.

Installing `Xvid`

Like most open source software, it is available in two flavors: official releases and the CVS version. The CVS version is usually stable enough to use, as most of the time it features fixes for bugs that exist in releases. Here is what to do to make `Xvid` CVS work with MEncoder (you need at least autoconf 2.50, automake and libtool):

1.     cvs -z3 -d:pserver:anonymous@cvs.xvid.org:/xvid login

2.     cvs -z3 -d:pserver:anonymous@cvs.xvid.org:/xvid co xvidcore

3.     cd xvidcore/build/generic

4.     ./bootstrap.sh

5.     ./configure

   You may have to add some options (examine the output of ./configure --help).

6.     make && make install

7. If you specified `--enable-divxcompat`, copy `../../src/divx4.h` to `/usr/local/include/`.

8. Recompile MPlayer with `--with-xvidlibdir=`/path/to/`libxvidcore.a` `--with-xvidincdir=`/path/to/`xvid.h`.

### 7.1.3. `x264`

#### 7.1.3.1. What is `x264`?

`x264` is a library for creating H.264 video streams. It is not 100% complete, but currently it has at least some kind of support for most of the H.264 features which impact quality. There are also many advanced features in the H.264 specification which have nothing to do with video quality per se; many of these are not yet implemented in `x264`.

Encoder features

- CAVLC/CABAC

- Multi-references

- Intra: all macroblock types (16x16, 8x8, and 4x4 with all predictions)

- Inter P: all partitions (from 16x16 down to 4x4)

- Inter B: partitions from 16x16 down to 8x8 (including SKIP/DIRECT)

- Ratecontrol: constant quantizer, constant bitrate, single or multipass ABR, optional VBV

- Scene cut detection

- Adaptive B-frame placement

- B-frames as references / arbitrary frame order

- 8x8 and 4x4 adaptive spatial transform

- Lossless mode

- Custom quantization matrices

- Parallel encoding of multiple slices

- Interlacing

#### 7.1.3.2. What is H.264?

H.264 is one name for a new digital video codec jointly developed by the ITU and MPEG. It can also be correctly referred to by the cumbersome names of "ISO/IEC 14496-10" or "MPEG-4 Part 10". More frequently, it is referred to as "MPEG-4 AVC" or just "AVC".

Whatever you call it, H.264 may be worth trying because it can typically match the quality of MPEG-4 ASP with 5%-30% less bitrate. Actual results will depend on both the source material and the encoder. The gains from using H.264 do not come for free: Decoding H.264 streams seems to have steep CPU and memory requirements. For instance, on a 1733 MHz Athlon, a DVD-resolution 1500kbps H.264 video requires around 35% CPU to decode. By comparison, decoding a DVD-resolution 1500kbps MPEG-4 ASP stream requires around 10% CPU. This means that decoding high-definition streams is almost out of the question for most users. It also means that even a decent DVD rip may sometimes stutter on processors slower than 2.0 GHz or so.

At least with `x264`, encoding requirements are not much worse than what you are used to with MPEG-4 ASP. For instance, on a 1733 MHz Athlon a typical DVD encode would run at 5-15fps.

This document is not intended to explain the details of H.264, but if you are interested in a brief overview, you may want to read The H.264/AVC Advanced Video Coding Standard: Overview and Introduction to the Fidelity Range Extensions.

#### 7.1.3.3. How can I play H.264 videos with MPlayer?

MPlayer uses `libavcodec`'s H.264 decoder. `libavcodec` has had at least minimally usable H.264 decoding since around July 2004, however major changes and improvements have been implemented since that time, both in terms of more functionalities supported and in terms of improved CPU usage. Just to be certain, it is always a good idea to use a recent Subversion checkout.

If you want a quick and easy way to know whether there have been recent changes to `libavcodec`'s H.264 decoding, you might keep an eye on FFmpeg Subversion repository's web interface.

#### 7.1.3.4. How can I encode videos using MEncoder and `x264`?

If you have the subversion client installed, the latest x264 sources can be gotten with this command:

    svn co svn://svn.videolan.org/x264/trunk x264

MPlayer sources are updated whenever an `x264` API change occurs, so it is always suggested to use MPlayer from Subversion as well. Perhaps this situation will change when and if an `x264` "release" occurs. Meanwhile, `x264` should be considered very unstable, in the sense that its programming interface is subject to change.

`x264` is built and installed in the standard way:

    ./configure && make && sudo make install

This installs libx264.a in /usr/local/lib and x264.h is placed in /usr/local/include. With the `x264` library and header placed in the standard locations, building MPlayer with `x264` support is easy. Just run the standard:

    ./configure && make && sudo make install

The `./configure` script will autodetect that you have satisfied the requirements for `x264`.

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