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author | Michael Niedermayer <michaelni@gmx.at> | 2011-10-22 01:03:27 +0200 |
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committer | Michael Niedermayer <michaelni@gmx.at> | 2011-10-22 01:16:41 +0200 |
commit | aedc908601de7396751a9a4504e064782d9f6a0b (patch) | |
tree | 8f04b899142439893bac426ac83d05c4068b099c /libavdevice/timefilter.h | |
parent | 1a7090bfafe986d4470ba8059c815939171ddb74 (diff) | |
parent | f4b51d061f0f34e36be876b562b8abe47f4b9c1c (diff) | |
download | ffmpeg-aedc908601de7396751a9a4504e064782d9f6a0b.tar.gz |
Merge remote-tracking branch 'qatar/master'
* qatar/master: (35 commits)
flvdec: Do not call parse_keyframes_index with a NULL stream
libspeexdec: include system headers before local headers
libspeexdec: return meaningful error codes
libspeexdec: cosmetics: reindent
libspeexdec: decode one frame at a time.
swscale: fix signed shift overflows in ff_yuv2rgb_c_init_tables()
Move timefilter code from lavf to lavd.
mov: add support for hdvd and pgapmetadata atoms
mov: rename function _stik, some indentation cosmetics
mov: rename function _int8 to remove ambiguity, some indentation cosmetics
mov: parse the gnre atom
mp3on4: check for allocation failures in decode_init_mp3on4()
mp3on4: create a separate flush function for MP3onMP4.
mp3on4: ensure that the frame channel count does not exceed the codec channel count.
mp3on4: set channel layout
mp3on4: fix the output channel order
mp3on4: allocate temp buffer with av_malloc() instead of on the stack.
mp3on4: copy MPADSPContext from first context to all contexts.
fmtconvert: port float_to_int16_interleave() 2-channel x86 inline asm to yasm
fmtconvert: port int32_to_float_fmul_scalar() x86 inline asm to yasm
...
Conflicts:
libavcodec/arm/h264dsp_init_arm.c
libavcodec/h264.c
libavcodec/h264.h
libavcodec/h264_cabac.c
libavcodec/h264_cavlc.c
libavcodec/h264_ps.c
libavcodec/h264dsp_template.c
libavcodec/h264idct_template.c
libavcodec/h264pred.c
libavcodec/h264pred_template.c
libavcodec/x86/h264dsp_mmx.c
libavdevice/Makefile
libavdevice/jack_audio.c
libavformat/Makefile
libavformat/flvdec.c
libavformat/flvenc.c
libavutil/pixfmt.h
libswscale/utils.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavdevice/timefilter.h')
-rw-r--r-- | libavdevice/timefilter.h | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/libavdevice/timefilter.h b/libavdevice/timefilter.h new file mode 100644 index 0000000000..4580904092 --- /dev/null +++ b/libavdevice/timefilter.h @@ -0,0 +1,97 @@ +/* + * Delay Locked Loop based time filter prototypes and declarations + * Copyright (c) 2009 Samalyse + * Copyright (c) 2009 Michael Niedermayer + * Author: Olivier Guilyardi <olivier samalyse com> + * Michael Niedermayer <michaelni gmx at> + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef AVDEVICE_TIMEFILTER_H +#define AVDEVICE_TIMEFILTER_H + +/** + * Opaque type representing a time filter state + * + * The purpose of this filter is to provide a way to compute accurate time + * stamps that can be compared to wall clock time, especially when dealing + * with two clocks: the system clock and a hardware device clock, such as + * a soundcard. + */ +typedef struct TimeFilter TimeFilter; + + +/** + * Create a new Delay Locked Loop time filter + * + * feedback2_factor and feedback3_factor are the factors used for the + * multiplications that are respectively performed in the second and third + * feedback paths of the loop. + * + * Unless you know what you are doing, you should set these as follow: + * + * o = 2 * M_PI * bandwidth * period + * feedback2_factor = sqrt(2 * o) + * feedback3_factor = o * o + * + * Where bandwidth is up to you to choose. Smaller values will filter out more + * of the jitter, but also take a longer time for the loop to settle. A good + * starting point is something between 0.3 and 3 Hz. + * + * @param clock_period period of the hardware clock in seconds + * (for example 1.0/44100) + * + * For more details about these parameters and background concepts please see: + * http://www.kokkinizita.net/papers/usingdll.pdf + */ +TimeFilter * ff_timefilter_new(double clock_period, double feedback2_factor, double feedback3_factor); + +/** + * Update the filter + * + * This function must be called in real time, at each process cycle. + * + * @param period the device cycle duration in clock_periods. For example, at + * 44.1kHz and a buffer size of 512 frames, period = 512 when clock_period + * was 1.0/44100, or 512/44100 if clock_period was 1. + * + * system_time, in seconds, should be the value of the system clock time, + * at (or as close as possible to) the moment the device hardware interrupt + * occured (or any other event the device clock raises at the beginning of a + * cycle). + * + * @return the filtered time, in seconds + */ +double ff_timefilter_update(TimeFilter *self, double system_time, double period); + +/** + * Reset the filter + * + * This function should mainly be called in case of XRUN. + * + * Warning: after calling this, the filter is in an undetermined state until + * the next call to ff_timefilter_update() + */ +void ff_timefilter_reset(TimeFilter *); + +/** + * Free all resources associated with the filter + */ +void ff_timefilter_destroy(TimeFilter *); + +#endif /* AVDEVICE_TIMEFILTER_H */ |