h261dec.c File Reference

H.261 decoder. More...

#include "libavutil/avassert.h"
#include "avcodec.h"
#include "mpegvideo.h"
#include "h263.h"
#include "h261.h"
#include "internal.h"

Go to the source code of this file.

Macros
#define	H261_MBA_VLC_BITS   9
#define	H261_MTYPE_VLC_BITS   6
#define	H261_MV_VLC_BITS   7
#define	H261_CBP_VLC_BITS   9
#define	TCOEFF_VLC_BITS   9
#define	MBA_STUFFING   33
#define	MBA_STARTCODE   34

Functions
static av_cold void	h261_decode_init_vlc (H261Context *h)
static av_cold int	h261_decode_init (AVCodecContext *avctx)
static int	h261_decode_gob_header (H261Context *h)
	Decode the group of blocks header or slice header.
static int	h261_resync (H261Context *h)
	Decode the group of blocks / video packet header.
static int	h261_decode_mb_skipped (H261Context *h, int mba1, int mba2)
	Decode skipped macroblocks.
static int	decode_mv_component (GetBitContext *gb, int v)
static int	h261_decode_block (H261Context *h, int16_t *block, int n, int coded)
	Decode a macroblock.
static int	h261_decode_mb (H261Context *h)
static int	h261_decode_picture_header (H261Context *h)
	Decode the H.261 picture header.
static int	h261_decode_gob (H261Context *h)
static int	get_consumed_bytes (MpegEncContext *s, int buf_size)
	returns the number of bytes consumed for building the current frame
static int	h261_decode_frame (AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
static av_cold int	h261_decode_end (AVCodecContext *avctx)

Variables
static VLC	h261_mba_vlc
static VLC	h261_mtype_vlc
static VLC	h261_mv_vlc
static VLC	h261_cbp_vlc
static const int	mvmap [17]
AVCodec	ff_h261_decoder

Detailed Description

H.261 decoder.

Definition in file h261dec.c.

Macro Definition Documentation

#define H261_MBA_VLC_BITS   9

Definition at line 35 of file h261dec.c.

Referenced by h261_decode_init_vlc(), and h261_decode_mb().

#define H261_MTYPE_VLC_BITS   6

Definition at line 36 of file h261dec.c.

Referenced by h261_decode_init_vlc(), and h261_decode_mb().

#define H261_MV_VLC_BITS   7

Definition at line 37 of file h261dec.c.

Referenced by decode_mv_component(), and h261_decode_init_vlc().

#define H261_CBP_VLC_BITS   9

Definition at line 38 of file h261dec.c.

Referenced by h261_decode_init_vlc(), and h261_decode_mb().

#define TCOEFF_VLC_BITS   9

Definition at line 39 of file h261dec.c.

Referenced by h261_decode_block().

#define MBA_STUFFING   33

Definition at line 40 of file h261dec.c.

Referenced by h261_decode_gob(), and h261_decode_mb().

#define MBA_STARTCODE   34

Definition at line 41 of file h261dec.c.

Referenced by h261_decode_mb().

Function Documentation

static av_cold void h261_decode_init_vlc ( H261Context *  h )

static

Definition at line 48 of file h261dec.c.

Referenced by h261_decode_init().

static av_cold int h261_decode_init ( AVCodecContext *  avctx )

static

Definition at line 70 of file h261dec.c.

static int h261_decode_gob_header ( H261Context *  h )

static

Decode the group of blocks header or slice header.

Returns

<0 if an error occurred

Definition at line 98 of file h261dec.c.

Referenced by h261_resync().

static int h261_resync ( H261Context *  h )

static

Decode the group of blocks / video packet header.

Returns

<0 if no resync found

Definition at line 152 of file h261dec.c.

Referenced by h261_decode_frame().

static int h261_decode_mb_skipped ( H261Context *  h, int  mba1, int  mba2  )

static

Decode skipped macroblocks.

Returns

0

Definition at line 193 of file h261dec.c.

Referenced by h261_decode_gob().

static int decode_mv_component ( GetBitContext *  gb, int  v  )

static

Definition at line 230 of file h261dec.c.

Referenced by h261_decode_mb().

static int h261_decode_block ( H261Context *  h, int16_t *  block, int  n, int  coded  )

static

Decode a macroblock.

Returns

<0 if an error occurred

Definition at line 256 of file h261dec.c.

Referenced by h261_decode_mb().

static int h261_decode_mb ( H261Context *  h )

static

Definition at line 340 of file h261dec.c.

Referenced by h261_decode_gob().

static int h261_decode_picture_header ( H261Context *  h )

static

Decode the H.261 picture header.

Returns

<0 if no startcode found

Definition at line 457 of file h261dec.c.

Referenced by h261_decode_frame().

static int h261_decode_gob ( H261Context *  h )

static

Definition at line 521 of file h261dec.c.

Referenced by h261_decode_frame().

static int get_consumed_bytes ( MpegEncContext *  s, int  buf_size  )

static

returns the number of bytes consumed for building the current frame

Definition at line 553 of file h261dec.c.

Referenced by h261_decode_frame().

static int h261_decode_frame ( AVCodecContext *  avctx, void *  data, int *  got_frame, AVPacket *  avpkt  )

static

Definition at line 564 of file h261dec.c.

static av_cold int h261_decode_end ( AVCodecContext *  avctx )

static

Definition at line 648 of file h261dec.c.

Variable Documentation

VLC h261_mba_vlc

static

Definition at line 43 of file h261dec.c.

VLC h261_mtype_vlc

static

Definition at line 44 of file h261dec.c.

VLC h261_mv_vlc

static

Definition at line 45 of file h261dec.c.

VLC h261_cbp_vlc

static

Definition at line 46 of file h261dec.c.

const int mvmap[17]

static

Initial value:

= {
    0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12, -13, -14, -15, -16
}

Definition at line 226 of file h261dec.c.

Referenced by decode_mv_component().

AVCodec ff_h261_decoder

Initial value:

= {
    .name           = "h261",
    .long_name      = NULL_IF_CONFIG_SMALL("H.261"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_H261,
    .priv_data_size = sizeof(H261Context),
    .init           = h261_decode_init,
    .close          = h261_decode_end,
    .decode         = h261_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
    .max_lowres     = 3,
}

Definition at line 657 of file h261dec.c.