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ffmpeg / libavcodec / bmpenc.c @ 72415b2a

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/*
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 * BMP image format encoder
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 * Copyright (c) 2006, 2007 Michel Bardiaux
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 * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "avcodec.h"
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#include "bytestream.h"
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#include "bmp.h"
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static const uint32_t monoblack_pal[] = { 0x000000, 0xFFFFFF };
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static const uint32_t rgb565_masks[]  = { 0xF800, 0x07E0, 0x001F };
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static av_cold int bmp_encode_init(AVCodecContext *avctx){
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    BMPContext *s = avctx->priv_data;
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    avcodec_get_frame_defaults((AVFrame*)&s->picture);
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    avctx->coded_frame = (AVFrame*)&s->picture;
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    return 0;
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}
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static int bmp_encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
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    BMPContext *s = avctx->priv_data;
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    AVFrame *pict = data;
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    AVFrame * const p= (AVFrame*)&s->picture;
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    int n_bytes_image, n_bytes_per_row, n_bytes, i, n, hsize;
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    const uint32_t *pal = NULL;
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    int pad_bytes_per_row, bit_count, pal_entries = 0, compression = BMP_RGB;
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    uint8_t *ptr;
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    unsigned char* buf0 = buf;
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    *p = *pict;
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    p->pict_type= FF_I_TYPE;
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    p->key_frame= 1;
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    switch (avctx->pix_fmt) {
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    case PIX_FMT_BGR24:
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        bit_count = 24;
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        break;
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    case PIX_FMT_RGB555:
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        bit_count = 16;
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        break;
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    case PIX_FMT_RGB565:
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        bit_count = 16;
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        compression = BMP_BITFIELDS;
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        pal = rgb565_masks; // abuse pal to hold color masks
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        pal_entries = 3;
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        break;
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    case PIX_FMT_RGB8:
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    case PIX_FMT_BGR8:
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    case PIX_FMT_RGB4_BYTE:
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    case PIX_FMT_BGR4_BYTE:
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    case PIX_FMT_GRAY8:
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    case PIX_FMT_PAL8:
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        bit_count = 8;
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        pal = (uint32_t *)p->data[1];
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        break;
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    case PIX_FMT_MONOBLACK:
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        bit_count = 1;
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        pal = monoblack_pal;
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        break;
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    default:
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        return -1;
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    }
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    if (pal && !pal_entries) pal_entries = 1 << bit_count;
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    n_bytes_per_row = ((int64_t)avctx->width * (int64_t)bit_count + 7LL) >> 3LL;
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    pad_bytes_per_row = (4 - n_bytes_per_row) & 3;
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    n_bytes_image = avctx->height * (n_bytes_per_row + pad_bytes_per_row);
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    // STRUCTURE.field refer to the MSVC documentation for BITMAPFILEHEADER
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    // and related pages.
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#define SIZE_BITMAPFILEHEADER 14
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#define SIZE_BITMAPINFOHEADER 40
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    hsize = SIZE_BITMAPFILEHEADER + SIZE_BITMAPINFOHEADER + (pal_entries << 2);
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    n_bytes = n_bytes_image + hsize;
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    if(n_bytes>buf_size) {
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        av_log(avctx, AV_LOG_ERROR, "buf size too small (need %d, got %d)\n", n_bytes, buf_size);
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        return -1;
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    }
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    bytestream_put_byte(&buf, 'B');                   // BITMAPFILEHEADER.bfType
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    bytestream_put_byte(&buf, 'M');                   // do.
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    bytestream_put_le32(&buf, n_bytes);               // BITMAPFILEHEADER.bfSize
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    bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved1
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    bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved2
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    bytestream_put_le32(&buf, hsize);                 // BITMAPFILEHEADER.bfOffBits
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    bytestream_put_le32(&buf, SIZE_BITMAPINFOHEADER); // BITMAPINFOHEADER.biSize
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    bytestream_put_le32(&buf, avctx->width);          // BITMAPINFOHEADER.biWidth
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    bytestream_put_le32(&buf, avctx->height);         // BITMAPINFOHEADER.biHeight
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    bytestream_put_le16(&buf, 1);                     // BITMAPINFOHEADER.biPlanes
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    bytestream_put_le16(&buf, bit_count);             // BITMAPINFOHEADER.biBitCount
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    bytestream_put_le32(&buf, compression);           // BITMAPINFOHEADER.biCompression
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    bytestream_put_le32(&buf, n_bytes_image);         // BITMAPINFOHEADER.biSizeImage
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    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biXPelsPerMeter
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    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biYPelsPerMeter
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    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrUsed
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    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrImportant
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    for (i = 0; i < pal_entries; i++)
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        bytestream_put_le32(&buf, pal[i] & 0xFFFFFF);
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    // BMP files are bottom-to-top so we start from the end...
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    ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
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    buf = buf0 + hsize;
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    for(i = 0; i < avctx->height; i++) {
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        if (bit_count == 16) {
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            const uint16_t *src = (const uint16_t *) ptr;
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            uint16_t *dst = (uint16_t *) buf;
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            for(n = 0; n < avctx->width; n++)
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                AV_WL16(dst + n, src[n]);
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        } else {
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            memcpy(buf, ptr, n_bytes_per_row);
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        }
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        buf += n_bytes_per_row;
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        memset(buf, 0, pad_bytes_per_row);
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        buf += pad_bytes_per_row;
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        ptr -= p->linesize[0]; // ... and go back
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    }
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    return n_bytes;
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}
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AVCodec bmp_encoder = {
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    "bmp",
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    AVMEDIA_TYPE_VIDEO,
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    CODEC_ID_BMP,
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    sizeof(BMPContext),
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    bmp_encode_init,
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    bmp_encode_frame,
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    NULL, //encode_end,
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    .pix_fmts = (const enum PixelFormat[]){
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        PIX_FMT_BGR24,
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        PIX_FMT_RGB555, PIX_FMT_RGB565,
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        PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE, PIX_FMT_GRAY8, PIX_FMT_PAL8,
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        PIX_FMT_MONOBLACK,
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        PIX_FMT_NONE},
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    .long_name = NULL_IF_CONFIG_SMALL("BMP image"),
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};