FFmpeg: libavcodec/bmpenc.c Source File

00001 /*
00002  * BMP image format encoder
00003  * Copyright (c) 2006, 2007 Michel Bardiaux
00004  * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
00005  *
00006  * This file is part of FFmpeg.
00007  *
00008  * FFmpeg is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * FFmpeg is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with FFmpeg; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00023 #include "libavutil/imgutils.h"
00024 #include "avcodec.h"
00025 #include "bytestream.h"
00026 #include "bmp.h"
00027 #include <assert.h>
00028 
00029 static const uint32_t monoblack_pal[] = { 0x000000, 0xFFFFFF };
00030 static const uint32_t rgb565_masks[]  = { 0xF800, 0x07E0, 0x001F };
00031 static const uint32_t rgb444_masks[]  = { 0x0F00, 0x00F0, 0x000F };
00032 
00033 static av_cold int bmp_encode_init(AVCodecContext *avctx){
00034     BMPContext *s = avctx->priv_data;
00035 
00036     avcodec_get_frame_defaults((AVFrame*)&s->picture);
00037     avctx->coded_frame = (AVFrame*)&s->picture;
00038 
00039     switch (avctx->pix_fmt) {
00040     case PIX_FMT_BGRA:
00041         avctx->bits_per_coded_sample = 32;
00042         break;
00043     case PIX_FMT_BGR24:
00044         avctx->bits_per_coded_sample = 24;
00045         break;
00046     case PIX_FMT_RGB555:
00047     case PIX_FMT_RGB565:
00048     case PIX_FMT_RGB444:
00049         avctx->bits_per_coded_sample = 16;
00050         break;
00051     case PIX_FMT_RGB8:
00052     case PIX_FMT_BGR8:
00053     case PIX_FMT_RGB4_BYTE:
00054     case PIX_FMT_BGR4_BYTE:
00055     case PIX_FMT_GRAY8:
00056     case PIX_FMT_PAL8:
00057         avctx->bits_per_coded_sample = 8;
00058         break;
00059     case PIX_FMT_MONOBLACK:
00060         avctx->bits_per_coded_sample = 1;
00061         break;
00062     default:
00063         av_log(avctx, AV_LOG_INFO, "unsupported pixel format\n");
00064         return -1;
00065     }
00066 
00067     return 0;
00068 }
00069 
00070 static int bmp_encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
00071     BMPContext *s = avctx->priv_data;
00072     AVFrame *pict = data;
00073     AVFrame * const p= (AVFrame*)&s->picture;
00074     int n_bytes_image, n_bytes_per_row, n_bytes, i, n, hsize;
00075     const uint32_t *pal = NULL;
00076     uint32_t palette256[256];
00077     int pad_bytes_per_row, pal_entries = 0, compression = BMP_RGB;
00078     int bit_count = avctx->bits_per_coded_sample;
00079     uint8_t *ptr;
00080     unsigned char* buf0 = buf;
00081     *p = *pict;
00082     p->pict_type= AV_PICTURE_TYPE_I;
00083     p->key_frame= 1;
00084     switch (avctx->pix_fmt) {
00085     case PIX_FMT_RGB444:
00086         compression = BMP_BITFIELDS;
00087         pal = rgb444_masks; // abuse pal to hold color masks
00088         pal_entries = 3;
00089         break;
00090     case PIX_FMT_RGB565:
00091         compression = BMP_BITFIELDS;
00092         pal = rgb565_masks; // abuse pal to hold color masks
00093         pal_entries = 3;
00094         break;
00095     case PIX_FMT_RGB8:
00096     case PIX_FMT_BGR8:
00097     case PIX_FMT_RGB4_BYTE:
00098     case PIX_FMT_BGR4_BYTE:
00099     case PIX_FMT_GRAY8:
00100         assert(bit_count == 8);
00101         ff_set_systematic_pal2(palette256, avctx->pix_fmt);
00102         pal = palette256;
00103         break;
00104     case PIX_FMT_PAL8:
00105         pal = (uint32_t *)p->data[1];
00106         break;
00107     case PIX_FMT_MONOBLACK:
00108         pal = monoblack_pal;
00109         break;
00110     }
00111     if (pal && !pal_entries) pal_entries = 1 << bit_count;
00112     n_bytes_per_row = ((int64_t)avctx->width * (int64_t)bit_count + 7LL) >> 3LL;
00113     pad_bytes_per_row = (4 - n_bytes_per_row) & 3;
00114     n_bytes_image = avctx->height * (n_bytes_per_row + pad_bytes_per_row);
00115 
00116     // STRUCTURE.field refer to the MSVC documentation for BITMAPFILEHEADER
00117     // and related pages.
00118 #define SIZE_BITMAPFILEHEADER 14
00119 #define SIZE_BITMAPINFOHEADER 40
00120     hsize = SIZE_BITMAPFILEHEADER + SIZE_BITMAPINFOHEADER + (pal_entries << 2);
00121     n_bytes = n_bytes_image + hsize;
00122     if(n_bytes>buf_size) {
00123         av_log(avctx, AV_LOG_ERROR, "buf size too small (need %d, got %d)\n", n_bytes, buf_size);
00124         return -1;
00125     }
00126     bytestream_put_byte(&buf, 'B');                   // BITMAPFILEHEADER.bfType
00127     bytestream_put_byte(&buf, 'M');                   // do.
00128     bytestream_put_le32(&buf, n_bytes);               // BITMAPFILEHEADER.bfSize
00129     bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved1
00130     bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved2
00131     bytestream_put_le32(&buf, hsize);                 // BITMAPFILEHEADER.bfOffBits
00132     bytestream_put_le32(&buf, SIZE_BITMAPINFOHEADER); // BITMAPINFOHEADER.biSize
00133     bytestream_put_le32(&buf, avctx->width);          // BITMAPINFOHEADER.biWidth
00134     bytestream_put_le32(&buf, avctx->height);         // BITMAPINFOHEADER.biHeight
00135     bytestream_put_le16(&buf, 1);                     // BITMAPINFOHEADER.biPlanes
00136     bytestream_put_le16(&buf, bit_count);             // BITMAPINFOHEADER.biBitCount
00137     bytestream_put_le32(&buf, compression);           // BITMAPINFOHEADER.biCompression
00138     bytestream_put_le32(&buf, n_bytes_image);         // BITMAPINFOHEADER.biSizeImage
00139     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biXPelsPerMeter
00140     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biYPelsPerMeter
00141     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrUsed
00142     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrImportant
00143     for (i = 0; i < pal_entries; i++)
00144         bytestream_put_le32(&buf, pal[i] & 0xFFFFFF);
00145     // BMP files are bottom-to-top so we start from the end...
00146     ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
00147     buf = buf0 + hsize;
00148     for(i = 0; i < avctx->height; i++) {
00149         if (bit_count == 16) {
00150             const uint16_t *src = (const uint16_t *) ptr;
00151             uint16_t *dst = (uint16_t *) buf;
00152             for(n = 0; n < avctx->width; n++)
00153                 AV_WL16(dst + n, src[n]);
00154         } else {
00155             memcpy(buf, ptr, n_bytes_per_row);
00156         }
00157         buf += n_bytes_per_row;
00158         memset(buf, 0, pad_bytes_per_row);
00159         buf += pad_bytes_per_row;
00160         ptr -= p->linesize[0]; // ... and go back
00161     }
00162     return n_bytes;
00163 }
00164 
00165 AVCodec ff_bmp_encoder = {
00166     .name           = "bmp",
00167     .type           = AVMEDIA_TYPE_VIDEO,
00168     .id             = CODEC_ID_BMP,
00169     .priv_data_size = sizeof(BMPContext),
00170     .init           = bmp_encode_init,
00171     .encode         = bmp_encode_frame,
00172     .pix_fmts = (const enum PixelFormat[]){
00173         PIX_FMT_BGRA, PIX_FMT_BGR24,
00174         PIX_FMT_RGB565, PIX_FMT_RGB555, PIX_FMT_RGB444,
00175         PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE, PIX_FMT_GRAY8, PIX_FMT_PAL8,
00176         PIX_FMT_MONOBLACK,
00177         PIX_FMT_NONE},
00178     .long_name = NULL_IF_CONFIG_SMALL("BMP image"),
00179 };