Abharana Bhat and Iain Richardson, May 2014
High efficiency video coding (HEVC) and Google / WebM VP9 are new codec formats designed to support HD and ultra HD streaming and broadcasting. This article explains how to start experimenting with HEVC and VP9 encoding. This is a short summary of the full article available at http://www.vcodex.com/h265.html.
1. HM reference software for HEVC
The HM software codec is a reference implementation of the HEVC coding
standard developed by the Joint Collaborative Team on Video Coding (JCT-VC). It
is suitable for experimenting with the various features available in the HEVC
coding standard and/or for checking compliance, but may not be suitable for
real-time implementations. The following steps will show you how to build and
run the HM codec.
Step 1: Get the source code
Step 2: Build the software according to the instructions here:
Step 3: Using the encoder
The HEVC encoder requires three inputs:
·
uncompressed (raw) YUV or Y4M file,
·
codec
configuration file
·
sequence
specific configuration file
For example, the following command line runs the HM encoder with codec configuration file encoder_randomaccess.cfg and sequence configuration file jockey.cfg.
./TAppEncoder
-c encoder_randomaccess.cfg -c jockey.cfg
Step 4: Decoding and playback
The encoder will output two files: a compressed .bin file and a reconstructed .yuv file. The YUV
file can be played back using a YUV player such as GLYUVPlay. GPAC’s Osmo4
player can playback the .bin file if you change the file extension from .bin to
.mp4.
2. x265 encoder for HEVC
x265 is an open source
software and library for HEVC encoding and decoding developed by a consortium led by MulticoreWare. It is available under the GNU
General Public License.
The software can be used
as a standalone tool or with FFMPEG as a library. The download and installation
instructions are as follows:
Step 1: Get the source
code and install instructions from https://bitbucket.org/multicoreware/x265/wiki/Home.
Step 2: Follow the install instructions. Check if
installation is successful by typing x265 at the terminal.
Step 3: The command line to
run the encoder is
x265 [options] infile [-o] outfile
where “infile” is an uncompressed source file (YUV or Y4M) and “outfile” is a compressed HEVC
bitstream.
Step 4: Use x265 as a library in
the FFMPEG framework
To use the x265 encoder
via FFMPEG, install x265 by following steps 1-4 and re-configure FFMPEG with
-enable-libx265.
The command line for using x265
library via FFMPEG is:
ffmpeg -i [input] -c:v libx265
[options] output[.265/.mkv]
FFMPEG
currently does not support the MP4 file format for HEVC files. You can use MP4Box
to convert .265 to mp4 format.
3. WebM VP9 codec
Step 1: Download and install the vp9 codec from
the WebM project website: http://www.webmproject.org/code/
Step 2 Type vpxenc at the command line to see if
the installation was successful.
Step 3: Example command line for running the vp9 encoder using vpxenc.
vpxenc --codec=vp9 --profile=0
--fps=50000/1001 --static-thresh=0 --drop-frame=0 --good --auto-alt-ref=1
--kf-min-dist=50 --kf-max-dist=50 --min-q=32 --max-q=32
--max-intra-rate=50 -threads 4 -w 1280 -h 720 --limit=500
in_to_tree_420_720p500.yuv -o in_to_tree_420_720p500_vp9_qp32.webm
Step 4: Decoding and playback
Option 1: convert to uncompressed YUV video using FFMPEG for
playback using the following command line:
ffmpeg -i input.webm -f rawvideo out.yuv
Option 2: use the latest version of VLC player
to playback the webm file.
To find out more
Visit http://www.vcodex.com/h265.html for a full version of this article and for more resources on HEVC, VP9 and other video codecs.
