Mercurial > SDL_sound_CoreAudio

comparison decoders/coreaudio.c @ 581:2264b134b7ac

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merged
author Eric Wing <ewing . public |-at-| gmail . com>
date Tue, 23 Nov 2010 18:25:44 -0800
parents 33a77ceaed26 6927c489964c
children
comparison
equal deleted inserted replaced
580:33a77ceaed26 581:2264b134b7ac
718 sample->flags |= SOUND_SAMPLEFLAG_ERROR; 718 sample->flags |= SOUND_SAMPLEFLAG_ERROR;
719 } 719 }
720 return(1); 720 return(1);
721 } /* CoreAudio_rewind */ 721 } /* CoreAudio_rewind */
722 722
723 723 /* Note: I found this tech note:
724 http://developer.apple.com/library/mac/#qa/qa2009/qa1678.html
725 I don't know if this applies to us. So far, I haven't noticed the problem,
726 so I haven't applied any of the techniques.
727 */
724 static int CoreAudio_seek(Sound_Sample *sample, Uint32 ms) 728 static int CoreAudio_seek(Sound_Sample *sample, Uint32 ms)
725 { 729 {
726 OSStatus error_result = noErr; 730 OSStatus error_result = noErr;
727 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque; 731 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
728 CoreAudioFileContainer* core_audio_file_container = (CoreAudioFileContainer *) internal->decoder_private; 732 CoreAudioFileContainer* core_audio_file_container = (CoreAudioFileContainer *) internal->decoder_private;
729 SInt64 frame_offset = 0; 733 SInt64 frame_offset = 0;
730 AudioStreamBasicDescription actual_format; 734 AudioStreamBasicDescription actual_format;
731 UInt32 format_size; 735 UInt32 format_size;
732 736
737
738 /* I'm confused. The Apple documentation says this:
739 "Seek position is specified in the sample rate and frame count of the file’s audio data format
740 — not your application’s audio data format."
741 My interpretation is that I want to get the "actual format of the file and compute the frame offset.
742 But when I try that, seeking goes to the wrong place.
743 When I use outputFormat, things seem to work correctly.
744 I must be misinterpreting the documentation or doing something wrong.
745 */
746 #if 0 /* not working */
733 format_size = sizeof(AudioStreamBasicDescription); 747 format_size = sizeof(AudioStreamBasicDescription);
734 error_result = AudioFileGetProperty( 748 error_result = AudioFileGetProperty(
735 *core_audio_file_container->audioFileID, 749 *core_audio_file_container->audioFileID,
736 kAudioFilePropertyDataFormat, 750 kAudioFilePropertyDataFormat,
737 &format_size, 751 &format_size,
742 sample->flags |= SOUND_SAMPLEFLAG_ERROR; 756 sample->flags |= SOUND_SAMPLEFLAG_ERROR;
743 BAIL_MACRO("Core Audio: Could not GetProperty for kAudioFilePropertyDataFormat.", 0); 757 BAIL_MACRO("Core Audio: Could not GetProperty for kAudioFilePropertyDataFormat.", 0);
744 } /* if */ 758 } /* if */
745 759
746 // packetIndex = (pos * sampleRate) / framesPerPacket 760 // packetIndex = (pos * sampleRate) / framesPerPacket
747 frame_offset = (SInt64)((ms/1000.0 * actual_format.mSampleRate) / actual_format.mFramesPerPacket); 761 // frame_offset = (SInt64)((ms/1000.0 * actual_format.mSampleRate) / actual_format.mFramesPerPacket);
762 #else /* seems to work, but I'm confused */
763 // packetIndex = (pos * sampleRate) / framesPerPacket
764 frame_offset = (SInt64)((ms/1000.0 * core_audio_file_container->outputFormat->mSampleRate) / core_audio_file_container->outputFormat->mFramesPerPacket);
765 #endif
766
748 // computed against actual format and not the client format 767 // computed against actual format and not the client format
749 error_result = ExtAudioFileSeek(core_audio_file_container->extAudioFileRef, frame_offset); 768 error_result = ExtAudioFileSeek(core_audio_file_container->extAudioFileRef, frame_offset);
750 if(error_result != noErr) 769 if(error_result != noErr)
751 { 770 {
752 sample->flags |= SOUND_SAMPLEFLAG_ERROR; 771 sample->flags |= SOUND_SAMPLEFLAG_ERROR;