Available as an Add-on to LEADTOOLS Multimedia toolkits. |
The LEAD AAC Transcoder Transcoder: A file format convertion
process that is executed by data re-packetizing. Transcoding avoids decoding
and re-compression thus providing speed gains over decoding-encoding methods
used in traditional filters. Additionally, LEADTOOLS transcoders preserve
data quality by avoiding re-compression of already compressed data.
is a DirectShow A multimedia framework and API produced by Microsoft for software developers
to perform various operations with media files. Most Windows video-related
applications on Windows, such as Microsoft's Windows Media Player, use
DirectShow to manage
multimedia content.® filter. It
is used to transcode AAC audio stream in mpeg2 format to ACC in ISO (mpeg4)
format or vice versa. This filter changes AAC packets format without performing
re-compression of the audio stream or the data packets. Converting with
this filter is fast, while the quality of the original stream is preserved.
To convert without re-compression, an AAC stream inside a MPEG2 transport
file to ISO format, or vice versa, LEAD AAC Transcoder filter should be
inserted between mpeg2 demux
and ISO multiplexer.
LEAD Multimedia toolkit automatically inserts the filter in this manner.
Filter Interfaces |
N/A |
Interface ID |
N/A |
Input Media Types |
Type: MEDIASUBTYPE_mp4a |
Output Media Types |
Type: MEDIASUBTYPE_AAC |
Filter CLSID |
CLSID_LMAACTranscoder |
Filter category |
CLSID_AudioCompressorCategory |
Executable |
LTranscoderAAC.dll, DSKernel2.dll |
Win32, x64
To illustrate the advantage of using transcoders, two setups are provided below for comparison. Observe (Figure 1) how the transcoders are positioned between LEAD MPEG Transport Demultiplexer and LEAD ISO Multiplexer. Now observe the next image (Figure 2) and how in between the same LEAD MPEG2 Transport Demultiplexer and LEAD ISO Multiplexer there is a need to use encoders and decoders. As a result of using decoding-encoding filters, the processing of data is slower than the speeds attained with data re-packetizing - a key feature of transcoders.
Figure 1. Re-packetizing of data using transcoders.
Figure 2. Decoding and encoding of data using filters.