[FFmpeg-devel] [PATCH] Add 1bpp, 8bpp, 15bpp, and 16bpp support to BMP encoder
Daniel Verkamp
daniel
Wed Mar 11 22:47:57 CET 2009
On Tue, Mar 10, 2009 at 6:14 PM, Stefan Gehrer <stefan.gehrer at gmx.de> wrote:
> Daniel Verkamp wrote:
> + ? ?n_bytes_per_row = (avctx->width * bit_count) >> 3;
> + ? ?pad_bytes_per_row = (4 - n_bytes_per_row) & 3;
> + ? ?n_bytes_image = avctx->height * (n_bytes_per_row + pad_bytes_per_row);
>
> For the case of PIX_FMT_MONOBLACK, a picture that is e.g. 36 pixels
> wide would only get 32 bit allocated for a line. Could that become
> a problem?
>
> Maybe
>
> n_bytes_per_row = (avctx->width * bit_count + 7) >> 3;
>
> would be enough to fix that.
>
> Stefan
Indeed, I didn't think the < 8 bit case through thoroughly enough -
fixed as you said.
Also changed in this round: masked palette entries to avoid any alpha
bits in the high byte leaking out, removed trailing whitespace from
one line.
Thanks,
-- Daniel Verkamp
-------------- next part --------------
>From 011ea3c4c559c534d13c6d7c6059ef726e95a77d Mon Sep 17 00:00:00 2001
From: Daniel Verkamp <daniel at drv.nu>
Date: Wed, 11 Mar 2009 16:48:24 -0500
Subject: [PATCH] Add 1bpp, 8bpp, 15bpp, and 16bpp support to BMP encoder
---
libavcodec/bmpenc.c | 72 +++++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 61 insertions(+), 11 deletions(-)
diff --git a/libavcodec/bmpenc.c b/libavcodec/bmpenc.c
index a54355c..f17c4a7 100644
--- a/libavcodec/bmpenc.c
+++ b/libavcodec/bmpenc.c
@@ -1,6 +1,7 @@
/*
* BMP image format encoder
* Copyright (c) 2006, 2007 Michel Bardiaux
+ * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
*
* This file is part of FFmpeg.
*
@@ -23,6 +24,9 @@
#include "bytestream.h"
#include "bmp.h"
+static const uint32_t monoblack_pal[] = { 0x000000, 0xFFFFFF };
+static const uint32_t rgb565_masks[] = { 0xF800, 0x07E0, 0x001F };
+
static av_cold int bmp_encode_init(AVCodecContext *avctx){
BMPContext *s = avctx->priv_data;
@@ -37,19 +41,52 @@ static int bmp_encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_s
AVFrame *pict = data;
AVFrame * const p= (AVFrame*)&s->picture;
int n_bytes_image, n_bytes_per_row, n_bytes, i, n, hsize;
+ const uint32_t *pal = NULL;
+ int pad_bytes_per_row, bit_count, pal_entries = 0, compression = BMP_RGB;
uint8_t *ptr;
unsigned char* buf0 = buf;
*p = *pict;
p->pict_type= FF_I_TYPE;
p->key_frame= 1;
- n_bytes_per_row = (avctx->width*3 + 3) & ~3;
- n_bytes_image = avctx->height*n_bytes_per_row;
+ switch (avctx->pix_fmt) {
+ case PIX_FMT_BGR24:
+ bit_count = 24;
+ break;
+ case PIX_FMT_RGB555:
+ bit_count = 16;
+ break;
+ case PIX_FMT_RGB565:
+ bit_count = 16;
+ compression = BMP_BITFIELDS;
+ pal = rgb565_masks; // abuse pal to hold color masks
+ pal_entries = 3;
+ break;
+ case PIX_FMT_RGB8:
+ case PIX_FMT_BGR8:
+ case PIX_FMT_RGB4_BYTE:
+ case PIX_FMT_BGR4_BYTE:
+ case PIX_FMT_GRAY8:
+ case PIX_FMT_PAL8:
+ bit_count = 8;
+ pal = (uint32_t *)p->data[1];
+ break;
+ case PIX_FMT_MONOBLACK:
+ bit_count = 1;
+ pal = monoblack_pal;
+ break;
+ default:
+ return -1;
+ }
+ if (pal && !pal_entries) pal_entries = 1 << bit_count;
+ n_bytes_per_row = (avctx->width * bit_count + 7) >> 3;
+ pad_bytes_per_row = (4 - n_bytes_per_row) & 3;
+ n_bytes_image = avctx->height * (n_bytes_per_row + pad_bytes_per_row);
// STRUCTURE.field refer to the MSVC documentation for BITMAPFILEHEADER
// and related pages.
#define SIZE_BITMAPFILEHEADER 14
#define SIZE_BITMAPINFOHEADER 40
- hsize = SIZE_BITMAPFILEHEADER + SIZE_BITMAPINFOHEADER;
+ hsize = SIZE_BITMAPFILEHEADER + SIZE_BITMAPINFOHEADER + (pal_entries << 2);
n_bytes = n_bytes_image + hsize;
if(n_bytes>buf_size) {
av_log(avctx, AV_LOG_ERROR, "buf size too small (need %d, got %d)\n", n_bytes, buf_size);
@@ -65,22 +102,30 @@ static int bmp_encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_s
bytestream_put_le32(&buf, avctx->width); // BITMAPINFOHEADER.biWidth
bytestream_put_le32(&buf, avctx->height); // BITMAPINFOHEADER.biHeight
bytestream_put_le16(&buf, 1); // BITMAPINFOHEADER.biPlanes
- bytestream_put_le16(&buf, 24); // BITMAPINFOHEADER.biBitCount
- bytestream_put_le32(&buf, BMP_RGB); // BITMAPINFOHEADER.biCompression
+ bytestream_put_le16(&buf, bit_count); // BITMAPINFOHEADER.biBitCount
+ bytestream_put_le32(&buf, compression); // BITMAPINFOHEADER.biCompression
bytestream_put_le32(&buf, n_bytes_image); // BITMAPINFOHEADER.biSizeImage
bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biXPelsPerMeter
bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biYPelsPerMeter
bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biClrUsed
bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biClrImportant
+ for (i = 0; i < pal_entries; i++)
+ bytestream_put_le32(&buf, pal[i] & 0xFFFFFF);
// BMP files are bottom-to-top so we start from the end...
ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
buf = buf0 + hsize;
for(i = 0; i < avctx->height; i++) {
- n = 3*avctx->width;
- memcpy(buf, ptr, n);
- buf += n;
- memset(buf, 0, n_bytes_per_row-n);
- buf += n_bytes_per_row-n;
+ if (bit_count == 16) {
+ const uint16_t *src = (const uint16_t *) ptr;
+ uint16_t *dst = (uint16_t *) buf;
+ for(n = 0; n < avctx->width; n++)
+ AV_WL16(dst + n, src[n]);
+ } else {
+ memcpy(buf, ptr, n_bytes_per_row);
+ }
+ buf += n_bytes_per_row;
+ memset(buf, 0, pad_bytes_per_row);
+ buf += pad_bytes_per_row;
ptr -= p->linesize[0]; // ... and go back
}
return n_bytes;
@@ -94,6 +139,11 @@ AVCodec bmp_encoder = {
bmp_encode_init,
bmp_encode_frame,
NULL, //encode_end,
- .pix_fmts= (enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_NONE},
+ .pix_fmts = (enum PixelFormat[]){
+ PIX_FMT_BGR24,
+ PIX_FMT_RGB555, PIX_FMT_RGB565,
+ PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE, PIX_FMT_GRAY8, PIX_FMT_PAL8,
+ PIX_FMT_MONOBLACK,
+ PIX_FMT_NONE},
.long_name = NULL_IF_CONFIG_SMALL("BMP image"),
};
--
1.6.2
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