Embedded Audio Coder (EAC) - Parser

Fig. 1 Functionality of the EAC parser.

The EAC parser converts a master embedded bitstream to an application bitstream of lower coding bitrate, number of audio channels, and audio sampling rate later. It needs a companion file for optimal scaling.

DOWNLOAD

The EAC parser can be download here. (In IE, when pop up download screen shows up, please use "save as" instead of "open". "Open" sometimes causes problem. )

You will need the Visual C++ runtime library (including msvcrt.dll etc) to use the EAC parser. The runtime libtrary can be downloaded here. (If you have question regarding the Visual C runtime library, please refer to this article. )

Currently, EAC parser is only available as a command line program in Windows platform. It may be run under cmd.exe, or cygwin (a UNIX environment developed by Redhat under Windows). Please contact the author if you request support for other platforms.

USAGE

EAC parser is a command line program with the following parameters

eac_parser -i INPUT.EAC -o OUTPUT.EAC -icomp ICOMPANION.COMP -rate RATE -ch CHANNEL -ss SAMPLING -ocomp OCOMPANION.COMP

The parameters of the EAC parser are as follows:

• -i INPUT.EAC : The master eac bitstream generated by a EAC encoder.
• -o OUTPUT.EAC : The output application EAC bitstream. The bitstream can be decoded (playered) by itself.
• -icomp ICOMPANION.COMP : The companion file of the master bitstream. [WARNING: EAC parser can perform bitstream scaling without the companion file. However, the compression performance will be poor. It is highly recommended to use a companion file in the scaling operation.]
• -rate RATE : The coding bitrate, in number of bits per second.
• -ch CHANNEL : For channel scaling. If the master bitstream is for stereo coding, and CHANNEL=1, the application bitstream will be mono (L+R channel if MIXER=1, L channel if MIXER=0 )
• -ss SAMPLING : For sampling rate scaling.
  • SAMPLING=0[default] : no sampling rate reduction.
  • SAMPLING=1: audio sampling rate is reduced by 1/2 (requires SPLIT=1 or 16)
  • SAMPLING=2: audio sampling rate is reduced by 1/4 (requires SPLIT=16)
• -ocomp OCOMPANION.COMP : The output companion file of the application bitstream. It is optional.

Examples

eac_parser -i mpeg_44m_64kbps.eac -o mpeg_44m_16kbps.eac -comp mpeg_44m.comp -rate 16384

Convert the master bitstream mpeg_44m_64kbps.eac (mono, 64kbps) to an application mpeg_44m_16kbps.eac of 16kbps.

eac_parser -i mpeg_44s_512kbps.eac -o mpeg_22m_16kbps.eac -icomp mpeg_44s.comp -rate 16384 -ss 1 -ch 1 -rate 16384

Convert the master bitstream mpeg_44s_512kbps.eac (stereo, 512kbps, 44.1kHz sampling) to an application bitstream mpeg_22m_16kbps.eac (mono, 16kbps, 22.05kHz sampling).

©Copyright by Jin Li, Apr. 23, 2002