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ffmpeg/libavcodec/cbs_vp9.c
Andreas Rheinhardt 14dd0a9057 avcodec/cbs: Avoid leaving the ... out in calls to variadic macros 
According to C99, there has to be at least one argument for every ...
in a variadic function-like macro. In practice most (all?) compilers also
allow to leave it completely out, but it is nevertheless required: In a
variadic macro "there shall be more arguments in the invocation than there
are parameters in the macro definition (excluding the ...)." (C99,
6.10.3.4).

CBS (not the framework itself, but the macros used in the
cbs_*_syntax_template.c files) relies on the compiler allowing to leave
a variadic macro argument out. This leads to warnings when compiling in
-pedantic mode, e.g. "warning: must specify at least one argument for
'...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]"
from Clang.

Most of these warnings can be easily avoided: The syntax_templates
mostly contain helper macros that expand to more complex variadic macros
and these helper macros often omit an argument for the .... Modifying
them to always expand to complex macros with an empty argument for the
... at the end fixes most of these warnings: The number of warnings went
down from 400 to 0 for cbs_av1, from 1114 to 32 for cbs_h2645, from 38 to
0 for cbs_jpeg, from 166 to 0 for cbs_mpeg2 and from 110 to 8 for cbs_vp9.

These eight remaining warnings for cbs_vp9 have been fixed by switching
to another macro in cbs_vp9_syntax_template: The fixed values for the
sync bytes as well as the trailing bits for byte-alignment are now read
via the fixed() macro (this also adds a check to ensure that trailing
bits are indeed zero as they have to be).

Reviewed-by: Mark Thompson <sw@jkqxz.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2020-04-12 23:23:49 +02:00

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/*
* 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
*/
#include "libavutil/avassert.h"
#include "cbs.h"
#include "cbs_internal.h"
#include "cbs_vp9.h"
#include "internal.h"
static int cbs_vp9_read_s(CodedBitstreamContext *ctx, GetBitContext *gbc,
int width, const char *name,
const int *subscripts, int32_t *write_to)
{
uint32_t magnitude;
int position, sign;
int32_t value;
if (ctx->trace_enable)
position = get_bits_count(gbc);
if (get_bits_left(gbc) < width + 1) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid signed value at "
"%s: bitstream ended.\n", name);
return AVERROR_INVALIDDATA;
}
magnitude = get_bits(gbc, width);
sign = get_bits1(gbc);
value = sign ? -(int32_t)magnitude : magnitude;
if (ctx->trace_enable) {
char bits[33];
int i;
for (i = 0; i < width; i++)
bits[i] = magnitude >> (width - i - 1) & 1 ? '1' : '0';
bits[i] = sign ? '1' : '0';
bits[i + 1] = 0;
ff_cbs_trace_syntax_element(ctx, position, name, subscripts,
bits, value);
}
*write_to = value;
return 0;
}
static int cbs_vp9_write_s(CodedBitstreamContext *ctx, PutBitContext *pbc,
int width, const char *name,
const int *subscripts, int32_t value)
{
uint32_t magnitude;
int sign;
if (put_bits_left(pbc) < width + 1)
return AVERROR(ENOSPC);
sign = value < 0;
magnitude = sign ? -value : value;
if (ctx->trace_enable) {
char bits[33];
int i;
for (i = 0; i < width; i++)
bits[i] = magnitude >> (width - i - 1) & 1 ? '1' : '0';
bits[i] = sign ? '1' : '0';
bits[i + 1] = 0;
ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
name, subscripts, bits, value);
}
put_bits(pbc, width, magnitude);
put_bits(pbc, 1, sign);
return 0;
}
static int cbs_vp9_read_increment(CodedBitstreamContext *ctx, GetBitContext *gbc,
uint32_t range_min, uint32_t range_max,
const char *name, uint32_t *write_to)
{
uint32_t value;
int position, i;
char bits[8];
av_assert0(range_min <= range_max && range_max - range_min < sizeof(bits) - 1);
if (ctx->trace_enable)
position = get_bits_count(gbc);
for (i = 0, value = range_min; value < range_max;) {
if (get_bits_left(gbc) < 1) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid increment value at "
"%s: bitstream ended.\n", name);
return AVERROR_INVALIDDATA;
}
if (get_bits1(gbc)) {
bits[i++] = '1';
++value;
} else {
bits[i++] = '0';
break;
}
}
if (ctx->trace_enable) {
bits[i] = 0;
ff_cbs_trace_syntax_element(ctx, position, name, NULL, bits, value);
}
*write_to = value;
return 0;
}
static int cbs_vp9_write_increment(CodedBitstreamContext *ctx, PutBitContext *pbc,
uint32_t range_min, uint32_t range_max,
const char *name, uint32_t value)
{
int len;
av_assert0(range_min <= range_max && range_max - range_min < 8);
if (value < range_min || value > range_max) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
"%"PRIu32", but must be in [%"PRIu32",%"PRIu32"].\n",
name, value, range_min, range_max);
return AVERROR_INVALIDDATA;
}
if (value == range_max)
len = range_max - range_min;
else
len = value - range_min + 1;
if (put_bits_left(pbc) < len)
return AVERROR(ENOSPC);
if (ctx->trace_enable) {
char bits[8];
int i;
for (i = 0; i < len; i++) {
if (range_min + i == value)
bits[i] = '0';
else
bits[i] = '1';
}
bits[i] = 0;
ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
name, NULL, bits, value);
}
if (len > 0)
put_bits(pbc, len, (1 << len) - 1 - (value != range_max));
return 0;
}
static int cbs_vp9_read_le(CodedBitstreamContext *ctx, GetBitContext *gbc,
int width, const char *name,
const int *subscripts, uint32_t *write_to)
{
uint32_t value;
int position, b;
av_assert0(width % 8 == 0);
if (ctx->trace_enable)
position = get_bits_count(gbc);
if (get_bits_left(gbc) < width) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid le value at "
"%s: bitstream ended.\n", name);
return AVERROR_INVALIDDATA;
}
value = 0;
for (b = 0; b < width; b += 8)
value |= get_bits(gbc, 8) << b;
if (ctx->trace_enable) {
char bits[33];
int i;
for (b = 0; b < width; b += 8)
for (i = 0; i < 8; i++)
bits[b + i] = value >> (b + i) & 1 ? '1' : '0';
bits[b] = 0;
ff_cbs_trace_syntax_element(ctx, position, name, subscripts,
bits, value);
}
*write_to = value;
return 0;
}
static int cbs_vp9_write_le(CodedBitstreamContext *ctx, PutBitContext *pbc,
int width, const char *name,
const int *subscripts, uint32_t value)
{
int b;
av_assert0(width % 8 == 0);
if (put_bits_left(pbc) < width)
return AVERROR(ENOSPC);
if (ctx->trace_enable) {
char bits[33];
int i;
for (b = 0; b < width; b += 8)
for (i = 0; i < 8; i++)
bits[b + i] = value >> (b + i) & 1 ? '1' : '0';
bits[b] = 0;
ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
name, subscripts, bits, value);
}
for (b = 0; b < width; b += 8)
put_bits(pbc, 8, value >> b & 0xff);
return 0;
}
#define HEADER(name) do { \
ff_cbs_trace_header(ctx, name); \
} while (0)
#define CHECK(call) do { \
err = (call); \
if (err < 0) \
return err; \
} while (0)
#define FUNC_NAME(rw, codec, name) cbs_ ## codec ## _ ## rw ## _ ## name
#define FUNC_VP9(rw, name) FUNC_NAME(rw, vp9, name)
#define FUNC(name) FUNC_VP9(READWRITE, name)
#define SUBSCRIPTS(subs, ...) (subs > 0 ? ((int[subs + 1]){ subs, __VA_ARGS__ }) : NULL)
#define f(width, name) \
xf(width, name, current->name, 0, )
#define s(width, name) \
xs(width, name, current->name, 0, )
#define fs(width, name, subs, ...) \
xf(width, name, current->name, subs, __VA_ARGS__)
#define ss(width, name, subs, ...) \
xs(width, name, current->name, subs, __VA_ARGS__)
#define READ
#define READWRITE read
#define RWContext GetBitContext
#define xf(width, name, var, subs, ...) do { \
uint32_t value; \
CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
SUBSCRIPTS(subs, __VA_ARGS__), \
&value, 0, (1 << width) - 1)); \
var = value; \
} while (0)
#define xs(width, name, var, subs, ...) do { \
int32_t value; \
CHECK(cbs_vp9_read_s(ctx, rw, width, #name, \
SUBSCRIPTS(subs, __VA_ARGS__), &value)); \
var = value; \
} while (0)
#define increment(name, min, max) do { \
uint32_t value; \
CHECK(cbs_vp9_read_increment(ctx, rw, min, max, #name, &value)); \
current->name = value; \
} while (0)
#define fle(width, name, subs, ...) do { \
CHECK(cbs_vp9_read_le(ctx, rw, width, #name, \
SUBSCRIPTS(subs, __VA_ARGS__), &current->name)); \
} while (0)
#define delta_q(name) do { \
uint8_t delta_coded; \
int8_t delta_q; \
xf(1, name.delta_coded, delta_coded, 0, ); \
if (delta_coded) \
xs(4, name.delta_q, delta_q, 0, ); \
else \
delta_q = 0; \
current->name = delta_q; \
} while (0)
#define prob(name, subs, ...) do { \
uint8_t prob_coded; \
uint8_t prob; \
xf(1, name.prob_coded, prob_coded, subs, __VA_ARGS__); \
if (prob_coded) \
xf(8, name.prob, prob, subs, __VA_ARGS__); \
else \
prob = 255; \
current->name = prob; \
} while (0)
#define fixed(width, name, value) do { \
av_unused uint32_t fixed_value; \
CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
0, &fixed_value, value, value)); \
} while (0)
#define infer(name, value) do { \
current->name = value; \
} while (0)
#define byte_alignment(rw) (get_bits_count(rw) % 8)
#include "cbs_vp9_syntax_template.c"
#undef READ
#undef READWRITE
#undef RWContext
#undef xf
#undef xs
#undef increment
#undef fle
#undef delta_q
#undef prob
#undef fixed
#undef infer
#undef byte_alignment
#define WRITE
#define READWRITE write
#define RWContext PutBitContext
#define xf(width, name, var, subs, ...) do { \
CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
SUBSCRIPTS(subs, __VA_ARGS__), \
var, 0, (1 << width) - 1)); \
} while (0)
#define xs(width, name, var, subs, ...) do { \
CHECK(cbs_vp9_write_s(ctx, rw, width, #name, \
SUBSCRIPTS(subs, __VA_ARGS__), var)); \
} while (0)
#define increment(name, min, max) do { \
CHECK(cbs_vp9_write_increment(ctx, rw, min, max, #name, current->name)); \
} while (0)
#define fle(width, name, subs, ...) do { \
CHECK(cbs_vp9_write_le(ctx, rw, width, #name, \
SUBSCRIPTS(subs, __VA_ARGS__), current->name)); \
} while (0)
#define delta_q(name) do { \
xf(1, name.delta_coded, !!current->name, 0, ); \
if (current->name) \
xs(4, name.delta_q, current->name, 0, ); \
} while (0)
#define prob(name, subs, ...) do { \
xf(1, name.prob_coded, current->name != 255, subs, __VA_ARGS__); \
if (current->name != 255) \
xf(8, name.prob, current->name, subs, __VA_ARGS__); \
} while (0)
#define fixed(width, name, value) do { \
CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
0, value, value, value)); \
} while (0)
#define infer(name, value) do { \
if (current->name != (value)) { \
av_log(ctx->log_ctx, AV_LOG_WARNING, "Warning: " \
"%s does not match inferred value: " \
"%"PRId64", but should be %"PRId64".\n", \
#name, (int64_t)current->name, (int64_t)(value)); \
} \
} while (0)
#define byte_alignment(rw) (put_bits_count(rw) % 8)
#include "cbs_vp9_syntax_template.c"
#undef WRITE
#undef READWRITE
#undef RWContext
#undef xf
#undef xs
#undef increment
#undef fle
#undef delta_q
#undef prob
#undef fixed
#undef infer
#undef byte_alignment
static int cbs_vp9_split_fragment(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag,
int header)
{
uint8_t superframe_header;
int err;
if (frag->data_size == 0)
return AVERROR_INVALIDDATA;
// Last byte in the packet.
superframe_header = frag->data[frag->data_size - 1];
if ((superframe_header & 0xe0) == 0xc0) {
VP9RawSuperframeIndex sfi;
GetBitContext gbc;
size_t index_size, pos;
int i;
index_size = 2 + (((superframe_header & 0x18) >> 3) + 1) *
((superframe_header & 0x07) + 1);
if (index_size > frag->data_size)
return AVERROR_INVALIDDATA;
err = init_get_bits(&gbc, frag->data + frag->data_size - index_size,
8 * index_size);
if (err < 0)
return err;
err = cbs_vp9_read_superframe_index(ctx, &gbc, &sfi);
if (err < 0)
return err;
pos = 0;
for (i = 0; i <= sfi.frames_in_superframe_minus_1; i++) {
if (pos + sfi.frame_sizes[i] + index_size > frag->data_size) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Frame %d too large "
"in superframe: %"PRIu32" bytes.\n",
i, sfi.frame_sizes[i]);
return AVERROR_INVALIDDATA;
}
err = ff_cbs_insert_unit_data(ctx, frag, -1, 0,
frag->data + pos,
sfi.frame_sizes[i],
frag->data_ref);
if (err < 0)
return err;
pos += sfi.frame_sizes[i];
}
if (pos + index_size != frag->data_size) {
av_log(ctx->log_ctx, AV_LOG_WARNING, "Extra padding at "
"end of superframe: %"SIZE_SPECIFIER" bytes.\n",
frag->data_size - (pos + index_size));
}
return 0;
} else {
err = ff_cbs_insert_unit_data(ctx, frag, -1, 0,
frag->data, frag->data_size,
frag->data_ref);
if (err < 0)
return err;
}
return 0;
}
static void cbs_vp9_free_frame(void *opaque, uint8_t *content)
{
VP9RawFrame *frame = (VP9RawFrame*)content;
av_buffer_unref(&frame->data_ref);
av_freep(&frame);
}
static int cbs_vp9_read_unit(CodedBitstreamContext *ctx,
CodedBitstreamUnit *unit)
{
VP9RawFrame *frame;
GetBitContext gbc;
int err, pos;
err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
if (err < 0)
return err;
err = ff_cbs_alloc_unit_content(ctx, unit, sizeof(*frame),
&cbs_vp9_free_frame);
if (err < 0)
return err;
frame = unit->content;
err = cbs_vp9_read_frame(ctx, &gbc, frame);
if (err < 0)
return err;
pos = get_bits_count(&gbc);
av_assert0(pos % 8 == 0);
pos /= 8;
av_assert0(pos <= unit->data_size);
if (pos == unit->data_size) {
// No data (e.g. a show-existing-frame frame).
} else {
frame->data_ref = av_buffer_ref(unit->data_ref);
if (!frame->data_ref)
return AVERROR(ENOMEM);
frame->data = unit->data + pos;
frame->data_size = unit->data_size - pos;
}
return 0;
}
static int cbs_vp9_write_unit(CodedBitstreamContext *ctx,
CodedBitstreamUnit *unit,
PutBitContext *pbc)
{
VP9RawFrame *frame = unit->content;
int err;
err = cbs_vp9_write_frame(ctx, pbc, frame);
if (err < 0)
return err;
// Frame must be byte-aligned.
av_assert0(put_bits_count(pbc) % 8 == 0);
if (frame->data) {
if (frame->data_size > put_bits_left(pbc) / 8)
return AVERROR(ENOSPC);
flush_put_bits(pbc);
memcpy(put_bits_ptr(pbc), frame->data, frame->data_size);
skip_put_bytes(pbc, frame->data_size);
}
return 0;
}
static int cbs_vp9_assemble_fragment(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag)
{
int err;
if (frag->nb_units == 1) {
// Output is just the content of the single frame.
CodedBitstreamUnit *frame = &frag->units[0];
frag->data_ref = av_buffer_ref(frame->data_ref);
if (!frag->data_ref)
return AVERROR(ENOMEM);
frag->data = frame->data;
frag->data_size = frame->data_size;
} else {
// Build superframe out of frames.
VP9RawSuperframeIndex sfi;
PutBitContext pbc;
AVBufferRef *ref;
uint8_t *data;
size_t size, max, pos;
int i, size_len;
if (frag->nb_units > 8) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Too many frames to "
"make superframe: %d.\n", frag->nb_units);
return AVERROR(EINVAL);
}
max = 0;
for (i = 0; i < frag->nb_units; i++)
if (max < frag->units[i].data_size)
max = frag->units[i].data_size;
if (max < 2)
size_len = 1;
else
size_len = av_log2(max) / 8 + 1;
av_assert0(size_len <= 4);
sfi.superframe_marker = VP9_SUPERFRAME_MARKER;
sfi.bytes_per_framesize_minus_1 = size_len - 1;
sfi.frames_in_superframe_minus_1 = frag->nb_units - 1;
size = 2;
for (i = 0; i < frag->nb_units; i++) {
size += size_len + frag->units[i].data_size;
sfi.frame_sizes[i] = frag->units[i].data_size;
}
ref = av_buffer_alloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!ref)
return AVERROR(ENOMEM);
data = ref->data;
memset(data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
pos = 0;
for (i = 0; i < frag->nb_units; i++) {
av_assert0(size - pos > frag->units[i].data_size);
memcpy(data + pos, frag->units[i].data,
frag->units[i].data_size);
pos += frag->units[i].data_size;
}
av_assert0(size - pos == 2 + frag->nb_units * size_len);
init_put_bits(&pbc, data + pos, size - pos);
err = cbs_vp9_write_superframe_index(ctx, &pbc, &sfi);
if (err < 0) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to write "
"superframe index.\n");
av_buffer_unref(&ref);
return err;
}
av_assert0(put_bits_left(&pbc) == 0);
flush_put_bits(&pbc);
frag->data_ref = ref;
frag->data = data;
frag->data_size = size;
}
return 0;
}
const CodedBitstreamType ff_cbs_type_vp9 = {
.codec_id = AV_CODEC_ID_VP9,
.priv_data_size = sizeof(CodedBitstreamVP9Context),
.split_fragment = &cbs_vp9_split_fragment,
.read_unit = &cbs_vp9_read_unit,
.write_unit = &cbs_vp9_write_unit,
.assemble_fragment = &cbs_vp9_assemble_fragment,
};
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