Go to the documentation of this file.
39 const int n = 1 <<
s->nbits;
41 const float k2 = 0.5 -
s->inverse;
55 #define RDFT_UNMANGLE(sign0, sign1) \
56 for (i = 1; i < (n>>2); i++) { \
60 ev.re = k1*(data[i1 ]+data[i2 ]); \
61 od.im = k2*(data[i2 ]-data[i1 ]); \
62 ev.im = k1*(data[i1+1]-data[i2+1]); \
63 od.re = k2*(data[i1+1]+data[i2+1]); \
65 odsum.re = od.re*tcos[i] sign0 od.im*tsin[i]; \
66 odsum.im = od.im*tcos[i] sign1 od.re*tsin[i]; \
67 data[i1 ] = ev.re + odsum.re; \
68 data[i1+1] = ev.im + odsum.im; \
69 data[i2 ] = ev.re - odsum.re; \
70 data[i2+1] = odsum.im - ev.im; \
73 if (
s->negative_sin) {
98 if (nbits < 4 || nbits > 16)
105 s->tcos = ff_cos_tabs[nbits];
106 s->tsin = ff_cos_tabs[nbits] + (
n >> 2);
#define ff_init_ff_cos_tabs
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
av_cold void ff_rdft_init_arm(RDFTContext *s)
av_cold void ff_rdft_end(RDFTContext *s)
static void rdft_calc_c(RDFTContext *s, FFTSample *data)
Map one real FFT into two parallel real even and odd FFTs.
#define RDFT_UNMANGLE(sign0, sign1)
av_cold int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans)
Set up a real FFT.
#define i(width, name, range_min, range_max)