xref: /third_party/ffmpeg/libavcodec/cljrenc.c (revision cabdff1a)
1/*
2 * Cirrus Logic AccuPak (CLJR) encoder
3 * Copyright (c) 2003 Alex Beregszaszi
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * Cirrus Logic AccuPak encoder.
25 */
26
27#include "libavutil/opt.h"
28
29#include "avcodec.h"
30#include "codec_internal.h"
31#include "encode.h"
32#include "put_bits.h"
33
34typedef struct CLJRContext {
35    AVClass        *avclass;
36    int             dither_type;
37} CLJRContext;
38
39static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
40                        const AVFrame *p, int *got_packet)
41{
42    CLJRContext *a = avctx->priv_data;
43    PutBitContext pb;
44    int x, y, ret;
45    uint32_t dither= avctx->frame_number;
46    static const uint32_t ordered_dither[2][2] =
47    {
48        { 0x10400000, 0x104F0000 },
49        { 0xCB2A0000, 0xCB250000 },
50    };
51
52    if (avctx->width%4 && avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL) {
53         av_log(avctx, AV_LOG_ERROR,
54                "Widths which are not a multiple of 4 might fail with some decoders, "
55                "use vstrict=-1 / -strict -1 to use %d anyway.\n", avctx->width);
56         return AVERROR_EXPERIMENTAL;
57    }
58
59    ret = ff_get_encode_buffer(avctx, pkt, 4 * avctx->height * ((avctx->width + 3) / 4), 0);
60    if (ret < 0)
61        return ret;
62
63    init_put_bits(&pb, pkt->data, pkt->size);
64
65    for (y = 0; y < avctx->height; y++) {
66        uint8_t *luma = &p->data[0][y * p->linesize[0]];
67        uint8_t *cb   = &p->data[1][y * p->linesize[1]];
68        uint8_t *cr   = &p->data[2][y * p->linesize[2]];
69        uint8_t luma_tmp[4];
70        for (x = 0; x < avctx->width; x += 4) {
71            switch (a->dither_type) {
72            case 0: dither = 0x492A0000;                       break;
73            case 1: dither = dither * 1664525 + 1013904223;    break;
74            case 2: dither = ordered_dither[ y&1 ][ (x>>2)&1 ];break;
75            }
76            if (x+3 >= avctx->width) {
77                memset(luma_tmp, 0, sizeof(luma_tmp));
78                memcpy(luma_tmp, luma, avctx->width - x);
79                luma = luma_tmp;
80            }
81            put_bits(&pb, 5, (249*(luma[3] +  (dither>>29)   )) >> 11);
82            put_bits(&pb, 5, (249*(luma[2] + ((dither>>26)&7))) >> 11);
83            put_bits(&pb, 5, (249*(luma[1] + ((dither>>23)&7))) >> 11);
84            put_bits(&pb, 5, (249*(luma[0] + ((dither>>20)&7))) >> 11);
85            luma += 4;
86            put_bits(&pb, 6, (253*(*(cb++) + ((dither>>18)&3))) >> 10);
87            put_bits(&pb, 6, (253*(*(cr++) + ((dither>>16)&3))) >> 10);
88        }
89    }
90
91    flush_put_bits(&pb);
92
93    *got_packet = 1;
94    return 0;
95}
96
97#define OFFSET(x) offsetof(CLJRContext, x)
98#define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
99static const AVOption options[] = {
100    { "dither_type",   "Dither type",   OFFSET(dither_type),        AV_OPT_TYPE_INT, { .i64=1 }, 0, 2, VE},
101    { NULL },
102};
103
104static const AVClass cljr_class = {
105    .class_name = "cljr encoder",
106    .item_name  = av_default_item_name,
107    .option     = options,
108    .version    = LIBAVUTIL_VERSION_INT,
109};
110
111const FFCodec ff_cljr_encoder = {
112    .p.name         = "cljr",
113    .p.long_name    = NULL_IF_CONFIG_SMALL("Cirrus Logic AccuPak"),
114    .p.type         = AVMEDIA_TYPE_VIDEO,
115    .p.id           = AV_CODEC_ID_CLJR,
116    .p.capabilities = AV_CODEC_CAP_DR1,
117    .priv_data_size = sizeof(CLJRContext),
118    FF_CODEC_ENCODE_CB(encode_frame),
119    .p.pix_fmts     = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV411P,
120                                                   AV_PIX_FMT_NONE },
121    .p.priv_class   = &cljr_class,
122};
123