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40 if (
c->high >= 0x8000) {
41 if (
c->low < 0x8000) {
42 if (
c->low >= 0x4000 &&
c->high < 0xC000) {
69 int range =
c->high -
c->low + 1;
70 int val = (((
c->value -
c->low + 1) <<
bits) - 1) / range;
73 c->high = ((
prob + range) >>
bits) +
c->low - 1;
83 int range =
c->high -
c->low + 1;
84 int val = ((
c->value -
c->low + 1) * mod_val - 1) / range;
87 c->high = (
prob + range) / mod_val +
c->low - 1;
88 c->low +=
prob / mod_val;
97 int range =
c->high -
c->low + 1;
98 int val = ((
c->value -
c->low + 1) * probs[0] - 1) / range;
101 while (probs[sym] >
val)
104 c->high = range * probs[sym - 1] / probs[0] +
c->low - 1;
105 c->low += range * probs[sym] / probs[0];
119 c->get_model_sym = arith_get_model_sym;
125 int i, ncol,
r,
g,
b;
126 uint32_t *pal =
ctx->pal + 256 -
ctx->free_colours;
128 if (!
ctx->free_colours)
132 for (
i = 0;
i < ncol;
i++) {
136 *pal++ = (0xFF
U << 24) | (
r << 16) | (
g << 8) |
b;
160 c->pal_pic =
ctx->pic->data[0] +
ctx->pic->linesize[0] * (avctx->
height - 1);
161 c->pal_stride = -
ctx->pic->linesize[0];
162 c->keyframe = !arith_get_bit(&acoder);
167 ctx->pic->key_frame = 1;
172 ctx->pic->key_frame = 0;
180 ctx->pic->palette_has_changed = pal_changed;
196 c->ctx.avctx = avctx;
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
static int get_bits_left(GetBitContext *gb)
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
static int arith_get_number(ArithCoder *c, int mod_val)
#define ARITH_GET_MODEL_SYM(prefix)
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
This structure describes decoded (raw) audio or video data.
static int arith_get_prob(ArithCoder *c, int16_t *probs)
static av_cold int mss1_decode_init(AVCodecContext *avctx)
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
static double val(void *priv, double ch)
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
@ AV_PICTURE_TYPE_I
Intra.
static unsigned int get_bits1(GetBitContext *s)
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
static av_cold int mss1_decode_end(AVCodecContext *avctx)
#define ARITH_GET_BIT(prefix)
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
const AVCodec ff_mss1_decoder
static int arith_get_bits(ArithCoder *c, int bits)
#define i(width, name, range_min, range_max)
static void arith_init(ArithCoder *c, GetBitContext *gb)
av_cold int ff_mss12_decode_end(MSS12Context *c)
const char * name
Name of the codec implementation.
static void arith_normalise(ArithCoder *c)
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Identical in function to ff_get_buffer(), except it reuses the existing buffer if available.
#define prob(name, subs,...)
main external API structure.
static int decode_pal(MSS12Context *ctx, ArithCoder *acoder)
int ff_mss12_decode_rect(SliceContext *sc, ArithCoder *acoder, int x, int y, int width, int height)
@ AV_PICTURE_TYPE_P
Predicted.
This structure stores compressed data.
void ff_mss12_slicecontext_reset(SliceContext *sc)
int width
picture width / height.
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
static int mss1_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
av_cold int ff_mss12_decode_init(MSS12Context *c, int version, SliceContext *sc1, SliceContext *sc2)