CodecBase

Overview

The CodecBase module provides the variables, attributes, and functions for basic audio and video multiplexing, demultiplexing, encoding, and decoding.

System capability: SystemCapability.Multimedia.Media.CodecBase

Since: 9

Files

Name	Description
avcodec_audio_channel_layout.h	Declares the enums used for audio codec channel layouts.
native_avcodec_base.h	Declares the native APIs used for basic audio and video multiplexing, demultiplexing, encoding, and decoding.

Media Codec Formats

The table below lists the media codec formats. The type is a constant string.

Name	Description
OH_AVCODEC_MIMETYPE_AUDIO_AAC	MIME type of the AAC audio codec.
OH_AVCODEC_MIMETYPE_AUDIO_FLAC	MIME type of the FLAC audio codec.
OH_AVCODEC_MIMETYPE_AUDIO_OPUS	MIME type of the Opus audio codec. (This specification is not available yet.)
OH_AVCODEC_MIMETYPE_AUDIO_G711MU	MIME type of the G.711 mu-law audio codec.
OH_AVCODEC_MIMETYPE_AUDIO_G711A	MIME type of the G.711 a-law audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_RAW	MIME type of raw audio streams.
OH_AVCODEC_MIMETYPE_AUDIO_VORBIS	MIME type of the Vorbis audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_MPEG	MIME type of the MP3 audio codec.
OH_AVCODEC_MIMETYPE_AUDIO_VIVID	MIME type of the Audio Vivid audio decoder. (This specification is not available yet.)
OH_AVCODEC_MIMETYPE_AUDIO_AMR_NB	MIME type of the AMR-NB audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_AMR_WB	MIME type of the AMR-WB audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_APE	MIME type of the APE audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_ALAC	MIME type of the Apple Lossless Audio Codec (ALAC) audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_AC3	MIME type of the Dolby Audio Coding 3 (AC 3) audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_EAC3	MIME type of the Enhanced AC-3 (EAC3) audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_WMAV1	MIME type of the Windows Media Audio (WMA) V1 audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_WMAV2	MIME type of the WMA V2 audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_WMAPRO	MIME type of the WMA Pro audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_GSM	MIME type of the Global System for Mobile Communications (GSM) audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_GSM_MS	MIME type of the GSM Microsoft variant (MS) audio decoder.
OH_AVCODEC_MIMETYPE_AUDIO_TWINVQ	MIME type of the Transform-domain Weighted Interleave Vector Quantization (TWINVQ) audio decoder. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_AUDIO_ILBC	MIME type of the Internet Low Bitrate Codec (ILBC) audio decoder. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_AUDIO_TRUEHD	MIME type of the True High Definition (TRUEHD) audio decoder. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_AUDIO_DVAUDIO	MIME type of the DVAUDIO (Digital Video Audio) audio decoder. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_AUDIO_DTS	MIME type of the DTS (Digital Theater Systems) audio decoder. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_AUDIO_COOK	MIME type of the Cook (RealAudio Cook) audio decoder. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_VIDEO_VVC	MIME type of the VVC (H.266) video codec.
OH_AVCODEC_MIMETYPE_VIDEO_HEVC	MIME type of the HEVC (H.265) video codec.
OH_AVCODEC_MIMETYPE_VIDEO_AVC	MIME type of the AVC (H.264) video codec.
OH_AVCODEC_MIMETYPE_VIDEO_H263	MIME type of the H.263 video codec.
OH_AVCODEC_MIMETYPE_VIDEO_VC1	MIME type of the VC-1 video codec. This specification is supported since API version 22.
OH_AVCODEC_MIMETYPE_VIDEO_MSVIDEO1	MIME type of the Microsoft Video 1 (MSVIDEO1) video codec. This specification is supported since API version 22.
OH_AVCODEC_MIMETYPE_VIDEO_WMV3	MIME type of the WMV3 video codec. This specification is supported since API version 22.
OH_AVCODEC_MIMETYPE_VIDEO_MJPEG	MIME type of the Motion JPEG (MJPEG) video codec. This specification is supported since API version 22.
OH_AVCODEC_MIMETYPE_VIDEO_MPEG4	MIME type of the MPEG4 video encoder, which is used only for multiplexing MPEG4 video streams. (It is deprecated from API version 11.)
OH_AVCODEC_MIMETYPE_VIDEO_MPEG4_PART2	MIME type of the MPEG4 Part 2 video codec.
OH_AVCODEC_MIMETYPE_VIDEO_MPEG2	MIME type of the MPEG2 video codec.
OH_AVCODEC_MIMETYPE_VIDEO_AV1	MIME type of the AV1 video codec. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_VIDEO_VP9	MIME type of the VP9 video codec. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_VIDEO_VP8	MIME type of the VP8 video codec. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_VIDEO_RV30	MIME type of the RV30 video codec. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_VIDEO_RV40	MIME type of the RV40 video codec. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_VIDEO_WVC1	MIME type of the WVC1 video codec. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_VIDEO_DVVIDEO	MIME type of the DVVIDEO (Digital Video) video codec. Supports DV NTSC, DV PAL, and DVCPRO HD. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_VIDEO_RAWVIDEO	MIME type of the RAWVIDEO video codec. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_VIDEO_MPEG1	MIME type of the MPEG1 video codec. This specification is supported since API version 23.
OH_AVCODEC_MIMETYPE_VIDEO_CINEPAK	MIME type of the Cinepak video codec. This key is supported since API version 24.
OH_AVCODEC_MIMETYPE_IMAGE_JPG	MIME type of the JPG image encoder, which is used only for multiplexing JPG covers.
OH_AVCODEC_MIMETYPE_IMAGE_PNG	MIME type of the PNG image encoder, which is used only for multiplexing PNG covers.
OH_AVCODEC_MIMETYPE_IMAGE_BMP	MIME type of the BMP image encoder, which is used only for multiplexing BMP covers.
OH_AVCODEC_MIMETYPE_SUBTITLE_WEBVTT	MIME type of the WEBVTT subtitle demuxer.
OH_AVCODEC_MIMETYPE_SUBTITLE_SRT	MIME type of the SRT subtitle demuxer.

Media Data Key-Value Pairs

The tables below list the key-value pairs used to describe media data. The key type is a constant string, and the value type can be int32_t, int64_t, float, double, char *, or uint8_t *.

The OH_AVFormat API is used to configure or query parameters.

Key-Value Pairs Dedicated for Capability Query

Name	Description
OH_FEATURE_PROPERTY_KEY_VIDEO_ENCODER_MAX_LTR_FRAME_COUNT	Maximum number of long-term reference (LTR) frames obtained during video encoding. The value type is int32_t.

Common Key-value Pairs of Audio and Video

Name	Description
OH_MD_KEY_CODEC_CONFIG	Codec-specific data. In the case of video, data carried in SPS/PPS is transferred. In the case of audio, data carried in extraData is transferred. The value type is uint8_t*. This key is optional. (This key is not supported yet for the video codec.)
OH_MD_MAX_INPUT_BUFFER_COUNT	Maximum number of input buffers. The value type is int32_t. This key is optional.
OH_MD_MAX_OUTPUT_BUFFER_COUNT	Maximum number of output buffers. The value type is int32_t. This key is optional.
OH_MD_KEY_BITRATE	Bit rate. The value type is int64_t. This key is used in audio and video encoding scenarios. It is optional in video encoding scenarios.
OH_MD_KEY_PROFILE	Encoding grading. The value type is int32_t. For details, see OH_AVCProfile, OH_HEVCProfile, and OH_AACProfile. This key is optional.
OH_MD_KEY_MAX_INPUT_SIZE	Maximum size of an input stream to decode. The value type is int32_t. This key is optional.
OH_MD_KEY_ENABLE_SYNC_MODE	Enabled status of audio/video codec synchronization. The value type is int32_t. 1 if enabled, 0 otherwise. This key is optional. By default, the feature is disabled. The key is used in the configuration phase.

Key-Value Pairs Dedicated for Video

Name	Description
OH_ED_KEY_TIME_STAMP	Surface buffer timestamp. The value is of the int64_t type. This key is optional. (It is deprecated from API version 14.)
OH_ED_KEY_EOS	End of stream for the surface buffer. The value type is int32_t. This key is optional. (It is deprecated from API version 14.)
OH_MD_KEY_WIDTH	Video width. The value type is int32_t.
OH_MD_KEY_HEIGHT	Video height. The value type is int32_t.
OH_MD_KEY_PIXEL_FORMAT	Video pixel format. The value type is int32_t. For details, see OH_AVPixelFormat.
OH_MD_KEY_FRAME_RATE	Video frame rate. The value type is double. This key is optional.
OH_MD_KEY_RANGE_FLAG	Video YUV value range flag. The value type is int32_t. The value 1 means a full range, and 0 means a limited range. This key is optional.
OH_MD_KEY_COLOR_PRIMARIES	Video primary colors. The value type is int32_t. For details, see OH_ColorPrimary. The value complies with Table 2 in H.273. This key is optional.
OH_MD_KEY_TRANSFER_CHARACTERISTICS	Video transfer characteristics. The value type is int32_t. For details, see OH_TransferCharacteristic. The value complies with Table 3 in H.273. This key is optional.
OH_MD_KEY_MATRIX_COEFFICIENTS	Video matrix coefficients. The value type is int32_t. For details, see OH_MatrixCoefficient. The value complies with Table 4 in H.273. This key is optional.
OH_MD_KEY_VIDEO_STRIDE	Stride of the video frame. The value type is int32_t. This key is optional.
OH_MD_KEY_VIDEO_SLICE_HEIGHT	Height of the video frame. The value type is int32_t. This key is optional.
OH_MD_KEY_VIDEO_PIC_WIDTH	Width of the video frame. The value type is int32_t. This key is optional.
OH_MD_KEY_VIDEO_PIC_HEIGHT	Height of the video frame. The value type is int32_t. This key is optional.
OH_MD_KEY_VIDEO_ENABLE_LOW_LATENCY	Enabled status of low-latency video codec. The value type is int32_t. 1 if enabled, 0 otherwise. This key is optional. By default, the feature is disabled. The key is used in the configuration phase.
OH_MD_KEY_VIDEO_ENCODE_BITRATE_MODE	Video encoding bit rate mode. The value type is int32_t. For details, see OH_BitrateMode. This key is optional.
OH_MD_KEY_QUALITY	Required encoding quality. The value type is int32_t. This key applies only to encoders configured in constant quality mode. This key is optional.
OH_MD_KEY_REQUEST_I_FRAME	Request for immediate encoding of I-frames. The value type is int32_t. This key is optional.
OH_MD_KEY_I_FRAME_INTERVAL	Key frame interval, in milliseconds. The value type is int32_t. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_ENCODER_ENABLE_TEMPORAL_SCALABILITY	Enabled status of temporal scalability. The value type is int32_t. 1 if enabled, 0 otherwise. This key is optional and used only for video encoding. By default, this feature is disabled. The key is used in the configuration phase.
OH_MD_KEY_VIDEO_ENCODER_TEMPORAL_GOP_SIZE	Size of a temporal image group. The value type is int32_t. This key is valid only when temporal scalability is enabled. This key is optional and used only in the configuration phase of video encoding.
OH_MD_KEY_VIDEO_ENCODER_TEMPORAL_GOP_REFERENCE_MODE	Reference mode in a temporal image group. The value type is int32_t. For details, see OH_TemporalGopReferenceMode. This key is valid only when temporal scalability is enabled. This key is optional and used only in the configuration phase of video encoding.
OH_MD_KEY_VIDEO_ENCODER_TEMPORAL_LAYER_ID	Temporal layer ID in a group of pictures (GOP). The value type is int32_t. Currently, this key is used only to query the temporal layer ID carried in AVBuffer output by the encoder. The procedure is as follows: 1. Use OH_AVCodecOnNewOutputBuffer or OH_VideoEncoder_GetOutputBuffer to obtain the buffer instance (AVBuffer). 2. Use OH_AVBuffer_GetParameter to obtain the parameter instance (OH_AVFormat), which does not contain basic properties. 3. Use OH_AVFormat_GetIntValue and this key to obtain the temporal layer ID of the corresponding frame. Since: 26.0.0
OH_MD_KEY_VIDEO_ENCODER_LTR_FRAME_COUNT	Number of LTR frames. The value type is int32_t. The value must be within the supported value range. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_ENCODER_PER_FRAME_MARK_LTR	Whether the current frame is marked as an LTR frame. The value type is int32_t. 1 if marked, 0 otherwise. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_ENCODER_PER_FRAME_USE_LTR	POC number of the LTR frame referenced by the current frame. The value type is int32_t. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_PER_FRAME_IS_LTR	Whether the frame corresponding to the stream output from the current OH_AVBuffer is marked as an LTR frame. The value type is int32_t. 1 if marked, 0 otherwise. This key is optional and used only for video encoding. The default value is 0.
OH_MD_KEY_VIDEO_PER_FRAME_POC	POC number of the frame. The value type is int32_t. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_ENCODER_QP_MAX	Maximum Quantization Parameter (QP) allowed by the video encoder. The value type is int32_t. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_ENCODER_QP_MIN	Minimum QP allowed by the video encoder. The value type is int32_t. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_ENCODER_QP_AVERAGE	Average QP of video frames. The value type is int32_t. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_ENCODER_MSE	Mean Squared Error (MSE) of video frames. The value type is double. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_ENCODER_REPEAT_PREVIOUS_FRAME_AFTER	Duration (in milliseconds) for which the last frame will be resubmitted repeatedly, if no new frame is available after the previous frame is submitted to the encoder. The value type is int32_t. This key is used only in the configuration phase of video encoding in surface mode.
OH_MD_KEY_VIDEO_ENCODER_REPEAT_PREVIOUS_MAX_COUNT	Maximum number of times the encoder can repeat encoding the previous frame when no new frame is available. The value type is int32_t. This key takes effect only when OH_MD_KEY_VIDEO_ENCODER_REPEAT_PREVIOUS_FRAME_AFTER is available and is used only in the configuration phase.
OH_MD_KEY_VIDEO_DECODER_OUTPUT_COLOR_SPACE	Output color space of the video decoder. The value type is int32_t. The supported value is OH_COLORSPACE_BT709_LIMIT.
OH_MD_KEY_ROTATION	Rotation angle of the surface, with a clockwise direction. The value type is int32_t, and the value range is {0, 90, 180, 270}. The default value is 0. This key is optional and is used only for video decoding in surface mode This key is optional.
OH_MD_KEY_SCALING_MODE	Video scaling mode. The value type is int32_t. For details, see OH_ScalingMode. This key is optional and is used only for video decoding in surface mode. You are advised to set the scaling mode by calling OH_NativeWindow_NativeWindowSetScalingModeV2. (It is deprecated from API version 14.)
OH_MD_KEY_VIDEO_CROP_TOP	Y-coordinate of the top edge of the crop rectangle. The value type is int32_t. This key is optional and is used only for video decoding.
OH_MD_KEY_VIDEO_CROP_BOTTOM	Y-coordinate of the bottom edge of the crop rectangle. The value type is int32_t. This key is optional and is used only for video decoding.
OH_MD_KEY_VIDEO_CROP_LEFT	X-coordinate of the left edge of the crop rectangle. The value type is int32_t. This key is optional and is used only for video decoding.
OH_MD_KEY_VIDEO_CROP_RIGHT	X-coordinate of the right edge of the crop rectangle. The value type is int32_t. This key is optional and is used only for video decoding.
OH_MD_KEY_VIDEO_DECODER_OUTPUT_ENABLE_VRR	Whether the decoder enables the video variable frame rate feature. The value type is int32_t. This key is optional and is used only for video decoding.
OH_MD_KEY_SQR_FACTOR	Quality parameter in SQR mode. The value range is [0, 51] (same as the QP value in encoding). A smaller value indicates a higher output bit rate and better quality. The value type is int32_t. This key is optional and is used only for video encoding.
OH_MD_KEY_MAX_BITRATE	Maximum bit rate in SQR mode. The value range can be obtained by calling OH_AVCapability_GetEncoderBitrateRange and is the same as that of OH_MD_KEY_BITRATE. The unit is bit/s. The value type is int64_t. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_ENCODER_ROI_PARAMS	ROI encoding parameters, including the ROI area and deltaQp. The value type is char *. This key is optional and is used only for video encoding.
OH_MD_KEY_VIDEO_ENCODER_ENABLE_PTS_BASED_RATECONTROL	Key for enabling the PTS-based bit rate control mode. The value type is int32_t. 1 to enable, 0 otherwise. This key is optional and used only for video encoding. The default value is 0. If this feature is enabled, each video frame must contain PTS information and be sent to the encoder. It is used in the configuration phase.
OH_MD_KEY_VIDEO_ENCODER_ENABLE_B_FRAME	Key for enabling bidirectional predictive frame (B-frame) encoding. The value type is int32_t. 1 to enable, 0 otherwise. This key is optional and used only for video encoding. The default value is 0. If enabled, the video encoder uses B-frame encoding, resulting in a decoding sequence different from the display sequence. For a device that does not support B-frame encoding, the configured key does not take effect. To check the device capability, use the OH_AVCapability_IsFeatureSupported API and the enumerated value OH_AVCapabilityFeature.VIDEO_ENCODER_B_FRAME. This key is used only by calling OH_VideoEncoder_Configure.
OH_MD_KEY_VIDEO_ENCODER_MAX_B_FRAMES	Pointer to the key that describes the maximum number of consecutive B-frames supported by the video encoder. The value type is int32_t. Note: This key is used only to query the encoder capability. The usage specifications are as follows: 1. To check whether the feature is supported, use the OH_AVCapability_IsFeatureSupported API and the enumerated value OH_AVCapabilityFeature.VIDEO_ENCODER_B_FRAME. 2. Obtain the OH_AVFormat pointer through the OH_AVCapability_GetFeatureProperties API and the enumerated value OH_AVCapabilityFeature.VIDEO_ENCODER_B_FRAME. 3. Obtain the maximum number of B-frames through the OH_AVFormat_GetIntValue API and this key.
OH_MD_KEY_VIDEO_DECODER_BLANK_FRAME_ON_SHUTDOWN	Pointer to the key that specifies whether to output blank frames when the video decoder is disabled. The value type is int32_t. 1 to output, 0 otherwise. The default value is 0. If this parameter is set to a non-zero value, the value 1 is used. This key is optional and is used only for video decoding in surface mode. After this feature is enabled, the video decoder outputs blank frames (usually black) when the OH_VideoDecoder_Stop or OH_VideoDecoder_Destroy API is called. This mechanism prevents frozen frames caused by sudden termination of the decoder.
OH_MD_KEY_VIDEO_NATIVE_BUFFER_FORMAT	Pointer to the key that is used to query the native buffer pixel format in video encoding and decoding. The value type is int32_t. For details, see the pixel formats defined in OH_NativeBuffer_Format. This key is used in the following scenarios: 1. Video decoding: Call OH_VideoDecoder_GetOutputDescription or OH_AVCodecOnStreamChanged to obtain the current output format from the returned OH_AVFormat object. 2. Video encoding: Call OH_VideoEncoder_GetInputDescription to obtain the current input format from the returned OH_AVFormat object.

Key-Value Pairs Dedicated for Audio

Name	Description
OH_MD_KEY_AUDIO_SAMPLE_FORMAT	Original audio format. The value type is int32_t. For details, see OH_BitsPerSample.
OH_MD_KEY_AUD_CHANNEL_COUNT	Number of audio channels. The value type is int32_t.
OH_MD_KEY_AUD_SAMPLE_RATE	Audio sampling rate. The value type is int32_t.
OH_MD_KEY_AUDIO_COMPRESSION_LEVEL	Audio codec compression level. The value type is int32_t type. This key is used only for audio encoding. This key is optional.
OH_MD_KEY_CHANNEL_LAYOUT	Required encoding channel layout. The value type is int64_t. This key applies only to encoders. For details, see OH_AudioChannelLayout.
OH_MD_KEY_BITS_PER_CODED_SAMPLE	Number of bits per sample. The value type is int32_t. This key is optional. In versions earlier than API version 20, this parameter must be set to 1 for FLAC encoding. Otherwise, OH_AudioCodec_Configure returns the error code AV_ERR_INVALID_VAL. However, this parameter has no actual effect and does not affect the encoding result. Starting from API version 20, you do not need to set it anymore.
OH_MD_KEY_SBR	AAC SBR format. The value type is int32_t. This key applies to AAC encoders. This key is optional.
OH_MD_KEY_COMPLIANCE_LEVEL	FLAC compliance level. The value type is int32_t. This key is used only for audio encoding. This key is optional.
OH_MD_KEY_AAC_IS_ADTS	AAC format, which can be ADTS or LATM. The value type is int32_t. This key applies to AAC decoders. This key is optional.
OH_MD_KEY_IDENTIFICATION_HEADER	Vorbis identification header. The value type is uint8_t*. This key applies only to Vorbis decoders. This key is optional.
OH_MD_KEY_SETUP_HEADER	Vorbis setup header. The value type is uint8_t*. This key applies only to Vorbis decoders. This key is optional.
OH_MD_KEY_AUDIO_OBJECT_NUMBER	Number of audio objects. The value type is int32_t. This key is used only for Audio Vivid decoding. This key is optional.
OH_MD_KEY_AUDIO_VIVID_METADATA	Audio Vivid metadata. The value type is uint8_t*. This key is used only for Audio Vivid decoding. This key is optional.
OH_MD_KEY_BLOCK_ALIGN	Size of the audio data block, in bytes. The value type is int32_t. This key is supported since API version 22 and must be configured only for WMAV1, WMAV2, and WMA PRO decoding.
OH_MD_KEY_ENABLE_BUFFER_SKIP_SAMPLES	Key for enabling OH_MD_KEY_BUFFER_SKIP_SAMPLES_INFO in the audio decoder. The value type is int32_t. 1 to enable, 0 otherwise. The default value is 0. If this parameter is set to a value other than 1, the value 0 is used. This key is optional. It is for the audio decoder only. This key is supported since API version 24.

Key-Value Pairs Dedicated for Multiplexing and Demultiplexing

Name	Description
OH_MD_KEY_VIDEO_IS_HDR_VIVID	Whether the video track in a media file is HDR Vivid. The value type is int32_t. This key is used for both multiplexing and demultiplexing. This key is optional.
OH_MD_KEY_START_TIME	Start time of the first frame in a media file, measured in microseconds. The value type is int64_t. This key is optional.
OH_MD_KEY_TRACK_START_TIME	Start time of the track, measured in microseconds. The value type is int64_t. This key is optional.
OH_MD_KEY_TRACK_TYPE	Track type in a media file. The value type is int32_t. For details, see OH_MediaType. This key is optional.
OH_MD_KEY_DURATION	Duration in a media file. The value type is int64_t. This key is optional.
OH_MD_KEY_TITLE	Title of a media file . The value type is char *. This key is optional.
OH_MD_KEY_ARTIST	Artist. The value type is char *. This key is optional.
OH_MD_KEY_ALBUM	Album media file. The value type is char *. This key is optional.
OH_MD_KEY_ALBUM_ARTIST	Album artist. The value type is char *. This key is optional.
OH_MD_KEY_DATE	Date of a media file, for example, 2024. The value type is char *. This key is optional.
OH_MD_KEY_COMMENT	Comment of a media file. The value type is char *. This key is optional.
OH_MD_KEY_GENRE	Genre in a media file. The value type is char *. This key is optional.
OH_MD_KEY_COPYRIGHT	Copyright of a media file. The value type is char *. This key is optional.
OH_MD_KEY_LANGUAGE	Language of a media file. The value type is char *. This key is optional.
OH_MD_KEY_DESCRIPTION	Description of a media file. The value type is char *. This key is optional.
OH_MD_KEY_LYRICS	Lyrics in a media file. The value type is char *. This key is optional.
OH_MD_KEY_TRACK_COUNT	Number of tracks in a media file. The value type is int32_t. This key is optional.
OH_MD_KEY_BUFFER_DURATION	Duration corresponding to the audio, video, or subtitle sample carried in AVBuffer, in microseconds. The value type is int64_t. This key is optional.
OH_MD_KEY_DECODING_TIMESTAMP	Decoding timestamp corresponding to the audio, video, or subtitle sample carried in AVBuffer, in microseconds. The value type is int64_t. This key is optional.
OH_MD_KEY_CODEC_MIME	MIME type of the codec. The value type is char *. This key is optional.
OH_MD_KEY_VIDEO_SAR	Aspect ratio of the sample. The value type is double.
OH_MD_KEY_CREATION_TIME	Media file creation time metadata. The value type is char *.
OH_MD_KEY_REFERENCE_TRACK_IDS	Reference relationship between media file tracks. The value type is int32_t*.
OH_MD_KEY_TRACK_REFERENCE_TYPE	Auxiliary track type of a media file. The value type is char *.
OH_MD_KEY_TRACK_DESCRIPTION	Auxiliary track description of a media file. The value type is char *.
OH_MD_KEY_BUFFER_SKIP_SAMPLES_INFO	Key carried in the OH_AVBuffer, which is supported only by demultiplexing. This key may be carried in the start and end frames of the audio output of demultiplexing. This key corresponds to a 10-byte uint8_t[] array, which records the number of audio samples to skip after decoding in the audio file metadata. The structure is as follows: 1. Bytes 0-3 (uint32_t, little-endian): number of samples to skip from the beginning of this frame. 2. Bytes 4-7 (uint32_t, little-endian): number of samples to skip from the end of this frame (must not exceed the frame's total sample count). 3. Bytes 8-9: reserved. The default output is 0. This key is supported since API version 23.
OH_MD_KEY_LATITUDE	Latitude key. The value is of the float type, and the value range is [-90.0, 90.0]. It indicates the latitude in geographic location information. This key is supported since API version 24.
OH_MD_KEY_LONGITUDE	Longitude key. The value is of the float type, and the value range is [-180.0, 180.0]. It indicates the longitude in geographic location information. This key is supported since API version 24.
OH_MD_KEY_ALTITUDE	Altitude key. The value is of the float type. This key is optional. It indicates the altitude in geographic location information. This key is supported since API version 24.