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Audio format information
#include <mm/types.h> typedef struct mm_audio_format { char codec[MM_CODEC_NAME_MAX_LEN]; uint32_t bitrate; uint32_t samplerate; uint8_t channels; uint8_t bitrate_type; uint8_t channel_type; uint8_t reserve1; int32_t reserve2; int32_t reserve3; } mm_audio_format_t;
The structure mm_audio_format_t provides information about the current state of an audio stream. It includes at least the members described in the table below.
Member | Type | Description |
---|---|---|
codec | char | Name of the audio codec. This member is the character string with the name of the audio codec. See “Audio codec” below. |
bitrate | uint32_t | Average bitrate for the audio track, in bits per second. |
samplerate | uint32_t | Sample bitrate, in hertz. |
channels | uint8_t | Channel type. See Audio channels. |
bitrate_type | uint8_t | Bitrate type. See mm_bitrate_t in this reference. |
channel_type | uint8_t | Deprecated in MME 1.1.0. Do not use. |
reserve1 | uint8_t | For future use. |
reserve2, 3 | int32_t | For future use. |
The MME API function mme_audio_get_status() uses the data structure mm_audio_format_t. The MME API function mme_video_get_status() uses the data structure mm_video_info_t. Both these structures include a member codec. The codec members of the structures mm_video_info_t and mm_audio_format_t hold character strings identifying the codec format for the video or audio. These strings can have a length of up to the number of bytes defined by MM_CODEC_NAME_MAX_LEN, which is currently 32 bytes.
Client applications can pass these character strings up to the end users to inform them of the codec format used by a video or audio track.
The channels member of the structure mm_audio_format_t describes the number of channels available in the audio stream. It can be set to any number defined as valid by the audio stream specification.
Channels | Audio stream |
---|---|
1 | mono |
2 | stereo |
6 | Dolby digital 5.1 |
6 | DTS |
8 | Dolby digital 7.1 |
8 | DTS_ES |
QNX Multimedia
mm_bitrate_t, mme_video_audio_info_t, mm_video_audio_info_t, mm_video_info_t, mme_audio_get_status, video_get_status()
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