75 lines
1.9 KiB
C
75 lines
1.9 KiB
C
#ifndef AUDIOPIPELINE_AUDIO_DEMUXER_MP3_H__INCLUDED
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#define AUDIOPIPELINE_AUDIO_DEMUXER_MP3_H__INCLUDED
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#include <stdbool.h>
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#include "audio.h"
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/**
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* Creates a demuxer element for MP3 files
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*
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* This demuxer just searches for MP3 sync markers, decodes the header to calculate frame length
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* and then will forward the MP3 data to the next element in the chain in packets of 10 frames.
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* The maximum size of data buffered before calling the decoder is around 14 kB.
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* The theoretical maximum decoded data from this packet is 11520 samples which could be
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* up to 45kB of data and between 0.96 and 1.44 seconds of audio playback time.
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*
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* Formula: FrameSize = (144 * BitRate / SampleRate) + PaddingBit
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*
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* @returns Initialized `AudioPipelineElement` that can be used in call to `audio_pipeline_assemble`
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*/
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AudioPipelineElement *audio_demuxer_mp3(void);
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typedef enum {
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MPEGVersion2_5 = 0,
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MPEGVersionReserved = 1,
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MPEGVersion2 = 2,
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MPEGVersion1 = 3
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} MPEGVersion;
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typedef enum {
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MPEGLayerReserved = 0,
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MPEGLayer3 = 1,
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MPEGLayer2 = 2,
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MPEGLayer1 = 3
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} MPEGLayer;
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typedef enum {
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MPEGChannelModeStereo = 0,
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MPEGChannelModeJointStereo = 1,
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MPEGChannelModeDualChannel = 2,
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MPEGChannelModeMono = 3
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} MPEGChannelMode;
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typedef enum {
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MPEGEmphasisNone = 0,
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MPEGEmphasis50_15 = 1,
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MPEGEmphasisReserved = 2,
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MPEGEmphasisCCITJ17 = 3
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} MPEGEmphasis;
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typedef struct _MP3Header {
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MPEGVersion version;
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MPEGLayer layer;
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uint8_t bitrateIndex;
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uint8_t sampleRateIndex;
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MPEGChannelMode channelMode;
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uint8_t jointStereoModeExtension;
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MPEGEmphasis emphasis;
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bool has_crc;
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bool has_padding;
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bool has_copyright;
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bool is_original;
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bool is_private;
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bool valid;
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uint32_t bitrate;
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uint32_t sampleRate;
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uint16_t packetLength;
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} MP3Header;
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MP3Header demuxer_mp3_decode_header(uint8_t data[4]);
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#endif /* AUDIOPIPELINE_AUDIO_DEMUXER_MP3_H__INCLUDED */
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