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• FFMPEG - Apple 720p30 Surround MP4 H.264 AAC stereo ; Dolby Digital

  10 décembre 2020, par Dean Van Greunen

  i would like the FFmpeg cli settings which will match this (this is a handbrake preset)

  


  

  


  Here is the presetting file, I dont understand what these would be for ffmpeg.

  


  {
    "AlignAVStart": false,
    "AudioCopyMask": [
      "copy:aac",
      "copy:ac3",
      "copy:dtshd",
      "copy:dts",
      "copy:mp3",
      "copy:truehd",
      "copy:flac",
      "copy:eac3"
    ],
    "AudioEncoderFallback": "ac3",
    "AudioLanguageList": [],
    "AudioList": [
      {
        "AudioBitrate": 160,
        "AudioCompressionLevel": 0.0,
        "AudioDitherMethod": null,
        "AudioEncoder": "av_aac",
        "AudioMixdown": "stereo",
        "AudioNormalizeMixLevel": false,
        "AudioSamplerate": "auto",
        "AudioTrackQualityEnable": false,
        "AudioTrackQuality": -1.0,
        "AudioTrackGainSlider": 0.0,
        "AudioTrackDRCSlider": 0.0
      },
      {
        "AudioBitrate": 640,
        "AudioCompressionLevel": 0.0,
        "AudioDitherMethod": null,
        "AudioEncoder": "copy:ac3",
        "AudioMixdown": "none",
        "AudioNormalizeMixLevel": false,
        "AudioSamplerate": "auto",
        "AudioTrackQualityEnable": false,
        "AudioTrackQuality": -1.0,
        "AudioTrackGainSlider": 0.0,
        "AudioTrackDRCSlider": 0.0
      }
    ],
    "AudioSecondaryEncoderMode": true,
    "AudioTrackSelectionBehavior": "first",
    "ChapterMarkers": true,
    "ChildrenArray": [],
    "Default": false,
    "FileFormat": "av_mp4",
    "Folder": false,
    "FolderOpen": false,
    "Mp4HttpOptimize": false,
    "Mp4iPodCompatible": false,
    "PictureAutoCrop": true,
    "PictureBottomCrop": 0,
    "PictureLeftCrop": 0,
    "PictureRightCrop": 0,
    "PictureTopCrop": 0,
    "PictureDARWidth": 0,
    "PictureDeblockPreset": "off",
    "PictureDeblockTune": "medium",
    "PictureDeblockCustom": "strength=strong:thresh=20:blocksize=8",
    "PictureDeinterlaceFilter": "decomb",
    "PictureCombDetectPreset": "default",
    "PictureCombDetectCustom": "",
    "PictureDeinterlacePreset": "default",
    "PictureDeinterlaceCustom": "",
    "PictureDenoiseCustom": "",
    "PictureDenoiseFilter": "off",
    "PictureDenoisePreset": "light",
    "PictureDenoiseTune": "none",
    "PictureSharpenCustom": "",
    "PictureSharpenFilter": "off",
    "PictureSharpenPreset": "medium",
    "PictureSharpenTune": "none",
    "PictureDetelecine": "off",
    "PictureDetelecineCustom": "",
    "PictureItuPAR": false,
    "PictureKeepRatio": true,
    "PictureLooseCrop": false,
    "PictureModulus": 2,
    "PicturePAR": "auto",
    "PicturePARWidth": 0,
    "PicturePARHeight": 0,
    "PictureRotate": null,
    "PictureWidth": 1280,
    "PictureHeight": 720,
    "PictureForceHeight": 0,
    "PictureForceWidth": 0,
    "PresetDescription": "H.264 video (up to 720p30), AAC stereo audio, and Dolby Digital (AC-3) surround audio, in an MP4 container. Compatible with Apple iPhone 4, 4S, and later; iPod touch 4th, 5th Generation and later; iPad 1st Generation, iPad 2, and later; Apple TV 2nd Generation and later.",
    "PresetName": "Apple 720p30 Surround",
    "Type": 0,
    "UsesPictureFilters": true,
    "UsesPictureSettings": 1,
    "SubtitleAddCC": false,
    "SubtitleAddForeignAudioSearch": true,
    "SubtitleAddForeignAudioSubtitle": false,
    "SubtitleBurnBehavior": "foreign",
    "SubtitleBurnBDSub": false,
    "SubtitleBurnDVDSub": false,
    "SubtitleLanguageList": [],
    "SubtitleTrackSelectionBehavior": "none",
    "VideoAvgBitrate": 3000,
    "VideoColorMatrixCode": 0,
    "VideoEncoder": "x264",
    "VideoFramerate": "30",
    "VideoFramerateMode": "pfr",
    "VideoGrayScale": false,
    "VideoScaler": "swscale",
    "VideoPreset": "medium",
    "VideoTune": "",
    "VideoProfile": "high",
    "VideoLevel": "3.1",
    "VideoOptionExtra": "",
    "VideoQualityType": 2,
    "VideoQualitySlider": 21.0,
    "VideoQSVDecode": false,
    "VideoQSVAsyncDepth": 4,
    "VideoTwoPass": true,
    "VideoTurboTwoPass": false,
    "x264Option": null,
    "x264UseAdvancedOptions": false
  },


  


• rename files for language_REGION according to the standard ISO_3166-1 (http://en.wikipedia.org/wiki/ISO_3166-1), for Taiwan tha language is Chinese (zh) and the region is Taiwan (TW)

  6 septembre 2012, par Coto

  m localization/messages_pt_BR.js m localization/messages_pt_PT.js m localization/messages_zh_TW.js rename files for language_REGION according to the standard ISO_3166-1 (http://en.wikipedia.org/wiki/ISO_3166-1), for Taiwan tha language is Chinese (zh) and the region is Taiwan (...)

• Meaning of Timestamp Retrieved by AudioQueueGetCurrentTime() in AudioQueue Callback

  30 juillet 2024, par White0930

  I'm working on an audio project and have a question regarding the meaning of the timestamp retrieved by AudioQueueGetCurrentTime().

  


  According to the Apple Developer Documentation, the following calculation gives the audio time being played (since AudioQueueStart) :

  


  - (Float64) GetCurrentTime {
    AudioTimeStamp c;       
    AudioQueueGetCurrentTime(playState.queue, NULL, &c, NULL);  
    return c.mSampleTime / _av->audio.sample_rate;
}


  


  However, in a project I'm working on, I noticed the following code inside the fillAudioBuffer callback function of AudioQueue :

  


  
static void fillAudioBuffer(AudioQueueRef queue, AudioQueueBufferRef buffer){
    
    int lengthCopied = INT32_MAX;
    int dts= 0;
    int isDone = 0;

    buffer->mAudioDataByteSize = 0;
    buffer->mPacketDescriptionCount = 0;
    
    OSStatus err = 0;
    AudioTimeStamp bufferStartTime;

    AudioQueueGetCurrentTime(queue, NULL, &bufferStartTime, NULL);
    

    
    while(buffer->mPacketDescriptionCount < numPacketsToRead && lengthCopied > 0){
        if (buffer->mAudioDataByteSize) {
            break;
        }
        
        lengthCopied = getNextAudio(_av,buffer->mAudioDataBytesCapacity-buffer->mAudioDataByteSize, (uint8_t*)buffer->mAudioData+buffer->mAudioDataByteSize,&dts,&isDone);
        if(!lengthCopied || isDone) break;
      
        if(aqStartDts < 0) aqStartDts = dts;
        if (dts>0) currentDts = dts;
        if(buffer->mPacketDescriptionCount ==0){
            bufferStartTime.mFlags = kAudioTimeStampSampleTimeValid;
            bufferStartTime.mSampleTime = (Float64)(dts-aqStartDts) * _av->audio.frame_size;
            
            if (bufferStartTime.mSampleTime <0 ) bufferStartTime.mSampleTime = 0;
            PMSG2("AQHandler.m fillAudioBuffer: DTS for %x: %lf time base: %lf StartDTS: %d\n", (unsigned int)buffer, bufferStartTime.mSampleTime, _av->audio.time_base, aqStartDts);
            
        }
        buffer->mPacketDescriptions[buffer->mPacketDescriptionCount].mStartOffset = buffer->mAudioDataByteSize;
        buffer->mPacketDescriptions[buffer->mPacketDescriptionCount].mDataByteSize = lengthCopied;
        buffer->mPacketDescriptions[buffer->mPacketDescriptionCount].mVariableFramesInPacket = _av->audio.frame_size;
        
        buffer->mPacketDescriptionCount++;
        buffer->mAudioDataByteSize += lengthCopied;
        
    }
    
#ifdef DEBUG
    int audioBufferCount, audioBufferTotal,  videoBufferCount, videoBufferTotal;
    bufferCheck(_av,&videoBufferCount, &videoBufferTotal, &audioBufferCount, &audioBufferTotal);
    
    PMSG2("AQHandler.m fillAudioBuffer: Video Buffer: %d/%d Audio Buffer: %d/%d\n", videoBufferCount, videoBufferTotal, audioBufferCount, audioBufferTotal);
    
    PMSG2("AQHandler.m fillAudioBuffer: Bytes copied for buffer 0x%x: %d\n",(unsigned int)buffer, (int)buffer->mAudioDataByteSize );
#endif  
    if(buffer->mAudioDataByteSize){
        
        if(err=AudioQueueEnqueueBufferWithParameters(queue, buffer, 0, NULL, 0, 0, 0, NULL, &bufferStartTime, NULL))
        {
#ifdef DEBUG
            char sErr[10];

            PMSG2(@"AQHandler.m fillAudioBuffer: Could not enqueue buffer 0x%x: %d %s.", buffer, err, FormatError(sErr, err));
#endif
        }
    }

}


  


  Based on the documentation for AudioQueueEnqueueBufferWithParameters and the variable naming used by the author, bufferStartTime seems to represent the time when the newly filled audio buffer will start playing, i.e., the time when all current audio in the queue has finished playing and the new audio starts. This interpretation suggests bufferStartTime is not the same as the time of the audio currently being played.

  


  I have browsed through many related questions, but I still have some doubts.. I'm currently fixing an audio-video synchronization issue in my project, and there isn't much detailed information in the Apple Developer Documentation (or maybe my search skills are lacking).

  


  Can someone clarify the exact meaning of the timestamp returned by AudioQueueGetCurrentTime() in this context ? Is it the time when the current audio will finish playing, or is it the time when the new audio will start playing ? Any additional resources or documentation that explain this in detail would also be appreciated.