EAC3 is output at 192khz, while AC3 is at 48khz. I dissassembled libaudioflinger.so and did binary edit to fix this. Shield ships both arm32 and aarch64 versions of those libs, but it seems. AC3 is the term for original lossy Dolby Digital. This is the original standard 5.1 format used by broadcast, DVD etc. EAC3 (E = Enhanced) is the newer Dolby Digital Plus format. It is still lossy but is more efficient than AC3 and can run at higher bitrates.
EAC3 to AC3 Conversion Softwareconverts EAC3 files to AC3 fast. The converter is a multiple channels encoder. The software supports 2.1, 4.0, 4.1, 5.1, 6.1, and 7.1 channels encoding for AAC, AC3, AIFF, AU, FLAC, OGG, and WAV files. The software also supports common file format such as OGG, MKA, AIFF, M4A (MPEG-4 audio), M4B (MPEG-4 audiobook), MPA, AC3, AAC for iPod/iPhone/iPad/iTunes/DSi, etc. It could convert TS to MP2, THD to AIFF, CAF to AC3, APE to M4B (MPEG-4 audiobook), DTS to MMF, MOV to VOC, and so on.
The EAC3 to AC3 Conversion Software is very easy to use and supports batch conversion. It is full compatible with 32-bit and 64-bit Windows 10/8/7/Vista/XP/2000.
What is EAC3?
Dolby Digital Plus (DD+ or E-AC-3 (Enhanced AC-3), and sometimes incorrectly asEC-3) is a digital audio compression scheme. It is an incompatible[1] developmentof the technologies used in the earlier Dolby Digital system. E-AC-3 has a numberof improvements aimed at increasing quality at a given bitrate compared with legacyDolby Digital (AC-3). While legacy AC-3 supports up to 5 full-range audio channelsat a coded bitrate of 0.640 Mbit/s, E-AC-3 supports up to 13 full range audiochannels at a coded bitrate of 6.144 Mbit/s peak.
Dolby Digital Plus bitstreams are not backward compatible with legacy DolbyDigital decoders, and decoders that output audio over legacy S/PDIF connectionsmust transcode the bitstreams to an older format such as PCM, AC-3, or DTS.
The codec used by Dolby Digital Plus is based on the original Dolby Digitalcodec, but with several enhancements to improve coding efficiency:
- Transient pre-noise processing - to reduce 'pre-noise' artifactsbefore sharp transients.
- Enhanced channel coupling - which maintains phase relationships between channels,and improves performance of matrix decoders.
- Adaptive hybrid transform processing - an improved bit allocation and quantizationalgorithm.
Dolby claims that these changes can result in bitrate improvements of up to50% while still allowing for the signal to be efficiently converted to Dolby Digitalfor backwards compatibility.
What is AC3?
Dolby Digital, or AC-3, is the common version containing up to six discrete channels of sound. The most elaborate mode in common usage involves five channels for normal-range speakers (20 Hz - 20,000 Hz) (right front, center, left front, right rear and left rear) and one channel (20 Hz - 120 Hz) for the subwoofer driven low-frequency effects. Mono and stereo modes are also supported. AC-3 supports audio sample-rates up to 48kHz. Batman Returns was the first film to use Dolby Digital technology when it premiered in theaters in Summer 1992. The LaserDisc version of Clear and Present Danger featured the first Home theater Dolby Digital mix in 1995.
Step-by-Step Instructions to Converting EAC3 to AC3:
- Install the software by instructions
- Launch EAC3 to AC3 Conversion Software
- Choose EAC3 Files
- Choose 'to AC3'
- Convert EAC3 to AC3
- Play and Browse AC3 File
Click 'Add Files' to choose EAC3 files and then add them to conversion list.
Choose one or more EAC3 files you want to convert and then click Open.
Click on 'Convert' to convert EAC3 files to AC3 format; alternatively, click on 'Convert to One' to convert all files in list and combine to a single one AC3 file.
The software is converting EAC3 files to AC3 format.
When conversion completes, you could right-click on converted file and choose 'Play Destination' to play the AC3 file; or choose 'Browse Destination Folder' to open Windows Explorer to browse the outputted AC3 file.
EAC3 to AC3 Conversion Software is 100% clean and safe to install. It's certified by major download sites.
EAC3 to AC3 Related Topics:
This documentation provides integration guidelines for application developers who need to support Dolby audio content.
You can see the Dolby settings in Amazon Fire TV by going to Settings > Display & Sounds > Audio > Dolby Digital Output.
- Option 2: Custom Media Player Approach
Terms
Note the following abbreviations used in this documentation:
- EAC3: Dolby Digital Plus (DDP)
- AC3: Dolby Digital (DD)
Ac3 And Eac3
Ac3 Vs Eac3 Pro
Four Ways to Play Dolby Audio
You can play Dolby (DD/DDP/Atmos) audio content in your app in four ways:
Option 1: Use ExoPlayer
ExoPlayer is a open source player supported by Google that supports playing Dolby audio stream.
Amazon has developed patches for Exoplayer to enable or enhance playback of Dolby audio content on variuos Amazon devices. These patches are open sourced here: exoplayer-amazon-port. (Note that each 'amazon/rx.y.z' branch maps to ExoPlayer version x.y.z.)
Option 2: Custom Media Player Approach
Implement a custom player that uses AudioManager, AudioTrack, and MediaCodec APIs. This section specifies the use of AudioManager, AudioTrack, and MediaCodec APIs to play Dolby audio content as recommended by Android.
Detecting Dolby support
Android L enhanced the ACTION_HDMI_AUDIO_PLUG intent in AudioManager to report the capabilities of sinks in Lollipop. This intent is broadcast whenever HDMI is plugged into or unplugged from to the device.
This intent also has a provision for apps to detect the capabilities of the connected endpoint (AVR or TV) via EXTRA_ENCODINGS present in the intent. The possible values are one of the ENCODING_XXXX values. For example:
- ENCODING_E_AC3_JOC (added in API level 28)
Android L does not have an enumeration type for Atmos(ENCODING_E_AC3_JOC) detection however we have an additional mechinism which exposes the information in the similar manner as EXTRA_ENCODINGS, by querying 'hdmi_encodings'
For example, if a sink supports Atmos the string returned will be:
NOTE: Certain platforms will indicate Dolby support even when the sink does not support decoding Dolby content. In this case the platform will transcode Dolby encoded content to the sink capabilities, for example, if the sink only supports PCM audio, the incoming Dolby audio stream will be transcoded to PCM by the Fire TV device.
Fire TV Edition TV platforms and sound bars outputting audio using the built in speakers (and not via an HDMI sink) do not have the above described ACTION_HDMI_AUDIO_PLUG boadcast action.
In this case applications shall query the global setting external_surround_sound_enabled to verify if Dolby decoding is supported by the device.
Return value of 1 indicates support.
The recommendation is if Dolby is supported to use passthrough playback, e.g. if using MediaCodec use the 'OMX.google.raw.dec' decoder.
For reference see Exoplayer patch (Added support for Surround Sound detection for Optical out)
Android API level 23 added an API getEncodings that can also query sink capabilities
The capabilities reported to applications can farther be effected by the Amazon Audio Settings, e.g. if Dolby is disabled the device will not report support for Dolby. This scenario does allow multichannel PCM when connected to a appropriate AVR.
AudioTrack Overview
Android L added the support of ENCODING_AC3 and ENCODING_E_AC3 encoding formats to AudioFormat. Android P added support for ENCODING_E_AC3_JOC used for Atmos. If the AudioTrack is configured with Dolby encoding format, and if the connecting endpoint supports that encoding format, AudioTrack accepts the Dolby raw bitstream as input and passes the bitstream to the endpoint after IEC61937 packetization. AudioTrack supports only clear (not encrypted) input bitstream.
What Is Ac3 Audio
Additionally, the creation of AudioTrack fails if the encoding format is not supported by the connected endpoint.
Certain platforms transcode DDP bitstream to DD if the connected endpoint only supports DD.
MediaCodec Overview
AudioTrack does not support Dolby audio content that is encrypted with DRM keys. Hence, for an encrypted Dolby audio bitstream, it is mandatory to use MediaCodec APIs to decrypt the bitstream and then pass the decrypted bitstream to AudioTrack.
Android provides a generic raw audio decoder via MediaCodec interface named 'OMX.google.raw.dec,' which is essentially a no-op (no operation) copy decoder. If the bitstream is encrypted, it uses MediaCrypto APIs to decrypt the bitstream and outputs it. Apps must use this decoder to decrypt the encrypted Dolby bitstream and pass the clear Dolby bitstream to AudioTrack.
Optionally, a platform can support Dolby decoder via MediaCodec interface. This decoder decodes the Dolby audio bitstream to PCM. Applications can use findDecoderForFormat to detect the presence of a decoder that supports Dolby MIME type.
Option 3: Use Other Supported Media Players
You can use other supported media players for Amazon Fire TV, such as VisualOn or NexPlayer, to play Dolby audio content and DRM content. Refer to Media Players for further details.
Option 4: Use Android Media Player
Your app can use Android MediaPlayer to play Dolby content.
Note: Android MediaPlayer can only output stereo PCM content and cannot support passthrough playback.
Handling non-Dolby End-Points and Private Listening Modes
This section describes recommendations and best practices for Dolby audio content playback on the Amazon Fire TV family of devices when connected to a non-Dolby endpoint and private listening(Bluetooth). Following these guidelines will help you create the best user experience for Dolby audio content playback.
As described previously, Android L introduced a new API in AudioManager called ACTION_HDMI_AUDIO_PLUG intent. This intent allows apps to detect the capabilities of the connected endpoint (AVR or TV). This detection can be used to support Dolby audio content playback in various HDMI related scenarios.
When connecting to a non HDMI sink device such as a Bluetooth headset the recommendation is to recreate the AudioTrack and switch to non-Dolby audio content such as AAC. This option has the advantage of reduced bandwidth usage as compared to Dolby audio content.
However, if the app cannot select an alternative non-Dolby audio content and chooses to continue to stream Dolby audio, applications should use MediaCodec to switch codecs from passthrough(OMX.google.raw.dec) to the appropriate Dolby codec(OMX.dolby.ac3.decoder or OMX.dolby.eac3.decoder).
The MediaCodec decoder decodes the Dolby bitstream, down-mixes to stereo PCM.
The AudioTrack again needs to be recreated with the ENCODING_PCM_16BIT audio format to render the PCM data.
Since the Dolby Decoder in all the platforms down-mixes multi-channel content to stereo, there is no real advantage in choosing Dolby audio content when the endpoint does not support DD or DDP.
Ffmpeg Ac3 Vs Eac3
When the TV is connected to a sound bar or AVR via Optical audio output or HDMI (based on the Dolby system settings set by the user on Fire TV Edition), an app can choose to stream surround sound in Dolby audio format.
To support this, the app is required to read a Global setting external_surround_sound_enabled to decide if surround sound (AC3 and EAC3) is supported or not. If the value is 1, Dolby audio is supported. If the value is 0, the app can further use other means (such as ACTION_HDMI_AUDIO_PLUG to decide if surround sound is supported or not.Refer to this Exoplayer patch (Added support for Surround Sound detection for Optical out for reference.
Ac3 Vs Dts
This assumes the Amazon device reports support for DD as well. In the event DD is not supported as described above an alternate non-Dolby audio track needs to be selected or the DDP content needs to be decoded to PCM.
Eac3 Vs Ac3 Quality
Last updated: Oct 29, 2020