. DM81xx AM38xx Audio Driver User Guide. Supports audio in stereo mode. Easy I2S/PCM audio interface setup between codec and SoC.
. В отличие от драйверов звуковых карт, ALSA также содержит. Пролистайте до каналов Master и PCM при помощи клавиш ← и. Стоит отметить, что это не даёт автоматического разложения на каналы стерео . SPDIF status: Disabled (Do not encode stereo PCM) Что бы установился драйвер надо устанавливать сначала Catalyst Software Suite. Думаю как раз для такой ниши и была разработана микросхема PCM5102А Очень интересый и. Тестился на. Вин ХР 32-бит. Драйвера XMOS-Stereo-USB-Audio-Class2-Driver-2022(v2.15).. Да и корректно отрабатывает тоже только стерео. а OUTPUT: PCM, 5.1 48000 Hz, 32-bit float и на ресе PCM уже а не DTS горит.
S/PDIF Pass- Through Transmission of Non- PCM Streams (Windows Drivers)The Sony/Philips digital interface (S/PDIF) format is defined primarily for transmitting PCM audio data, but it can easily be adapted to transmit non- PCM data. The principle of S/PDIF pass- through transmission is that a non- PCM data stream can pass through an S/PDIF link as though it were a PCM stream. Pass- through transmission does not require the S/PDIF sending and receiving ports to understand the encoding of the non- PCM stream.
WMA Pro and AC- 3 are both compressed non- PCM formats that transmit digital audio streams in units called synchronization frames. Each sync frame contains its own header and can be decoded independently of the other sync frames in the stream. At a 4. 8- k. Hz sample rate, for example, a WMA Pro sync frame contains enough data to play for 2. At this same rate, an AC- 3 sync frame contains enough data for 1. At a 4. 8- k. Hz sample rate, a 5. WMA Pro sync frame never exceeds 8. PCM samples. Similarly, a 5.
AC- 3 sync frame never exceeds 6. PCM samples. (There are exceptions to this rule, but those types of AC- 3 sync frames are very uncommon, cannot be transmitted over S/PDIF, and can be ignored here.)When a 4. Hz WMA Pro or AC- 3 audio stream passes through an S/PDIF link in digital form without being decoded, the S/PDIF sending and receiving ports can treat the stream the same as a stereo, 1. Hz PCM stream. When specifying a data range for a pin that can transmit a WMA Pro- over- S/PDIF or AC- 3- over- S/PDIF stream, the wave- format tag itself is the only thing that differs from a data range for a pin that transmits a PCM stream through the S/PDIF port.
For an example, see the data range declarations in Specifying WMA Pro Data Ranges. In order to avoid delivering a WMA Pro compressed stream over the S/PDIF interface faster than real time (that is, to prevent delivery of 4.
WMA Pro sync frame with zeros until the sync frame takes up the same number of bytes as 2. PCM samples. An AC- 3 sync frame must similarly be padded out to the size of 1. PCM samples. If you attempt to send unpadded WMA Pro or AC- 3 sync frames to a Port. Cls adapter driver that uses Wave. Cyclic, be aware that when the port driver senses data starvation (because the data stream contains fewer bytes than a two- channel uncompressed stream would), it fills the cyclic buffer with silence. The non- PCM stream decoder will have problems interpreting these periods of silence, which are in PCM rather than the non- PCM format. The following figure shows an example application of S/PDIF pass- through transmission.
The figure shows a PC connected to an external audio/visual (A/V) receiver through a coaxial cable. The cable connects the S/PDIF output port on the PC's audio device to the S/PDIF input port on the A/V receiver. At the left edge of the figure, an audio application inserts a sync frame from a WMA Pro audio stream into the beginning of an 8. This buffer size is used purely for ease of illustration.
In practice, a buffer size of 4. The application fills any remaining space in the buffer with zeros. The audio driver programs the S/PDIF output port to transmit the contents of the buffer as though they were 8. PCM data. Similarly, the S/PDIF input port on the A/V receiver receives the stream as though it were 8. PCM data. It loads the data into an input buffer, which in this example also has a size of 8. The decoder extracts the WMA Pro sync frame from the input buffer, decodes the sync frame into a 5. To let the decoder on the other end of the connection know that the audio stream is in a non- PCM format, the audio driver should set the /AUDIO bit on the S/PDIF transceiver.
The decoder reads this bit from the S/PDIF channel- status block to determine whether the data stream is encoded in a non- PCM format. Setting this bit is the only thing special that the driver needs to do to accommodate the non- PCM stream.
In every other way, the driver treats the stream as though it contains PCM data. A number of consumer devices support S/PDIF pass- through transmission, but other digital interfaces such as USB and 1. PCM data to external audio decoders. Dolby Laboratories introduced the AC- 3 (Dolby Digital) compressed audio format in 1. The first consumer A/V receivers to support AC- 3 over S/PDIF became available in about 1.
Software support for the WMA Pro audio stream format became available with the release of the Microsoft Windows Media 9 Series technology in 2. A/V receivers that support WMA Pro- over- S/PDIF were introduced in 2. In Windows XP and later, the wave. Out, Direct. Sound, and Direct. Show APIs support non- PCM formats. The Direct. Sound and wave. Out APIs are implemented in such a way that any PCM or non- PCM format that the driver exposes is automatically available to clients of these APIs.
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