FFmpeg: libswscale/ops_backend.c Source File

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libswscale

ops_backend.c

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1 /**

3 *

4 * This file is part of FFmpeg.

5 *

6 * FFmpeg is free software; you can redistribute it and/or

7 * modify it under the terms of the GNU Lesser General Public

8 * License as published by the Free Software Foundation; either

9 * version 2.1 of the License, or (at your option) any later version.

10 *

11 * FFmpeg is distributed in the hope that it will be useful,

12 * but WITHOUT ANY WARRANTY; without even the implied warranty of

13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

14 * Lesser General Public License for more details.

15 *

16 * You should have received a copy of the GNU Lesser General Public

17 * License along with FFmpeg; if not, write to the Free Software

18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

19 */

21 #include "ops_backend.h"

23 #if AV_GCC_VERSION_AT_LEAST(4, 4)

24 #pragma GCC optimize ("finite-math-only")

25 #endif

27 /* Array-based reference implementation */

29 #ifndef SWS_BLOCK_SIZE

30 # define SWS_BLOCK_SIZE 32

31 #endif

33 typedef uint8_t u8block_t[SWS_BLOCK_SIZE];

34 typedef uint16_t u16block_t[SWS_BLOCK_SIZE];

35 typedef uint32_t u32block_t[SWS_BLOCK_SIZE];

36 typedef float f32block_t[SWS_BLOCK_SIZE];

38 #define BIT_DEPTH 8

39 # include "ops_tmpl_int.c"

40 #undef BIT_DEPTH

42 #define BIT_DEPTH 16

43 # include "ops_tmpl_int.c"

44 #undef BIT_DEPTH

46 #define BIT_DEPTH 32

47 # include "ops_tmpl_int.c"

48 # include "ops_tmpl_float.c"

49 #undef BIT_DEPTH

51 static void process(const SwsOpExec *exec, const void *priv,

52 const int bx_start, const int y_start, int bx_end, int y_end)

53 {

54 const SwsOpChain *chain = priv;

55 const SwsOpImpl *impl = chain->impl;

56 SwsOpIter iter;

58 for (iter.y = y_start; iter.y < y_end; iter.y++) {

59 for (int i = 0; i < 4; i++) {

60 iter.in[i] = exec->in[i] + (iter.y - y_start) * exec->in_stride[i];

61 iter.out[i] = exec->out[i] + (iter.y - y_start) * exec->out_stride[i];

62 }

64 for (int block = bx_start; block < bx_end; block++) {

65 iter.x = block * SWS_BLOCK_SIZE;

66 ((void (*)(SwsOpIter *, const SwsOpImpl *)) impl->cont)

67 (&iter, &impl[1]);

68 }

69 }

70 }

72 static int compile(SwsContext *ctx, SwsOpList *ops, SwsCompiledOp *out)

73 {

74 int ret;

76 SwsOpChain *chain = ff_sws_op_chain_alloc();

77 if (!chain)

78 return AVERROR(ENOMEM);

80 static const SwsOpTable *const tables[] = {

81 &bitfn(op_table_int, u8),

82 &bitfn(op_table_int, u16),

83 &bitfn(op_table_int, u32),

84 &bitfn(op_table_float, f32),

85 };

87 do {

88 ret = ff_sws_op_compile_tables(tables, FF_ARRAY_ELEMS(tables), ops,

89 SWS_BLOCK_SIZE, chain);

90 } while (ret == AVERROR(EAGAIN));

91 if (ret < 0) {

92 ff_sws_op_chain_free(chain);

93 return ret;

94 }

96 *out = (SwsCompiledOp) {

97 .func = process,

98 .block_size = SWS_BLOCK_SIZE,

99 .cpu_flags = chain->cpu_flags,

100 .priv = chain,

101 .free = ff_sws_op_chain_free_cb,

102 };

103 return 0;

104 }

105

106 const SwsOpBackend backend_c = {

107 .name = "c",

108 .compile = compile,

109 };

SwsOpTable

Definition: ops_chain.h:122

compile

static int compile(SwsContext *ctx, SwsOpList *ops, SwsCompiledOp *out)

Definition: ops_backend.c:72

AVERROR

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

ops_backend.h

f32block_t

float f32block_t[SWS_BLOCK_SIZE]

Definition: ops_backend.c:36

out

FILE * out

Definition: movenc.c:55

SwsOpExec::out_stride

ptrdiff_t out_stride[4]

Definition: ops_internal.h:63

SwsOpExec::in

const uint8_t * in[4]

Definition: ops_internal.h:58

SwsOpImpl::cont

SwsFuncPtr cont

Definition: ops_chain.h:68

backend_c

const SwsOpBackend backend_c

Definition: ops_backend.c:106

SwsOpIter

Definition: ops_backend.h:46

SwsOpExec::in_stride

ptrdiff_t in_stride[4]

Definition: ops_internal.h:62

SwsOpIter::out

uint8_t * out[4]

Definition: ops_backend.h:48

SwsOpBackend::name

const char * name

Definition: ops_internal.h:104

SwsOpChain::cpu_flags

int cpu_flags

Definition: ops_chain.h:85

SwsOpIter::x

int x

Definition: ops_backend.h:49

tables

Writing a table generator This documentation is preliminary Parts of the API are not good and should be changed Basic concepts A table generator consists of two *_tablegen c and *_tablegen h The h file will provide the variable declarations and initialization code for the tables

Definition: tablegen.txt:10

FF_ARRAY_ELEMS

#define FF_ARRAY_ELEMS(a)

Definition: sinewin_tablegen.c:29

u8block_t

uint8_t u8block_t[SWS_BLOCK_SIZE]

Definition: ops_backend.c:33

ff_sws_op_chain_alloc

SwsOpChain * ff_sws_op_chain_alloc(void)

Definition: ops_chain.c:29

u16block_t

uint16_t u16block_t[SWS_BLOCK_SIZE]