[FFmpeg-devel] [PATCH] PCX encoder

Daniel Verkamp daniel
Fri Mar 20 00:41:55 CET 2009


On Thu, Mar 19, 2009 at 3:48 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Thu, Mar 19, 2009 at 12:33:41PM -0400, Daniel Verkamp wrote:
>> On Wed, Mar 18, 2009 at 9:23 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
>> > On Tue, Mar 17, 2009 at 01:14:50PM -0400, Daniel Verkamp wrote:
>> > [...]
>> >> +static int pcx_rle_encode( ? ? ?uint8_t *dst, int dst_size,
>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ?const uint8_t *src, int src_size)
>> >> +{
>> >> + ? ?int i;
>> >> + ? ?uint8_t prev = src[0];
>> >> + ? ?int count = 1;
>> >> + ? ?const uint8_t *dst_start = dst;
>> >> +
>> >> + ? ?// check worst-case upper bound on dst_size
>> >> + ? ?if (dst_size < 2LL * src_size)
>> >> + ? ? ? ?return -1;
>> >> +
>> >> + ? ?for (i = 1; ; i++) {
>> >> + ? ? ? ?if (i != src_size && src[i] == prev && count < 0x3F) {
>> >> + ? ? ? ? ? ?// current byte is same as prev
>> >> + ? ? ? ? ? ?++count;
>> >> + ? ? ? ?} else {
>> >> + ? ? ? ? ? ?// output prev * count
>> >> + ? ? ? ? ? ?if (count != 1 || prev >= 0xC0)
>> >> + ? ? ? ? ? ? ? ?*dst++ = 0xC0 | count;
>> >> + ? ? ? ? ? ?*dst++ = prev;
>> >> +
>> >> + ? ? ? ? ? ?if (i == src_size)
>> >> + ? ? ? ? ? ? ? ?return dst - dst_start;
>> >> +
>> >> + ? ? ? ? ? ?// start new run
>> >> + ? ? ? ? ? ?count = 1;
>> >> + ? ? ? ? ? ?prev = src[i];
>> >> + ? ? ? ?}
>> >> + ? ?}
>> >> +
>> >> + ? ?return 0; // gcc warns even though this cannot be reached
>> >
>> > does gcc still warn with the current for() ?
>> >
>>
>> Eliminated in latest patch.
>>
>> >
>> >> +}
>> >> +
>> >> +static int pcx_encode_frame(AVCodecContext *avctx,
>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ?unsigned char *buf, int buf_size, void *data)
>> >> +{
>> >> + ? ?PCXContext *s = avctx->priv_data;
>> >> + ? ?AVFrame *const pict = &s->picture;
>> >> + ? ?const uint8_t *buf_start = buf;
>> >> + ? ?const uint8_t *buf_end ? = buf + buf_size;
>> >> +
>> >> + ? ?int bpp, nplanes, i, j, y, p, line_bytes, written, src_line_size;
>> >> + ? ?const uint32_t *pal = NULL;
>> >> + ? ?const uint8_t *src;
>> >> + ? ?uint8_t *plane;
>> >> +
>> >> + ? ?*pict = *(AVFrame *)data;
>> >> + ? ?pict->pict_type = FF_I_TYPE;
>> >> + ? ?pict->key_frame = 1;
>> >> +
>> >> + ? ?if (avctx->width > 65535 || avctx->height > 65535) {
>> >> + ? ? ? ?av_log(avctx, AV_LOG_ERROR, "image dimensions do not fit in 16 bits\n");
>> >> + ? ? ? ?return -1;
>> >> + ? ?}
>> >> +
>> >> + ? ?switch (avctx->pix_fmt) {
>> >> + ? ?case PIX_FMT_RGB24:
>> >> + ? ? ? ?bpp = 8;
>> >> + ? ? ? ?nplanes = 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:
>> >> + ? ? ? ?bpp = 8;
>> >> + ? ? ? ?nplanes = 1;
>> >> + ? ? ? ?pal = (uint32_t *)pict->data[1];
>> >> + ? ? ? ?break;
>> >> + ? ?case PIX_FMT_MONOBLACK:
>> >> + ? ? ? ?bpp = 1;
>> >> + ? ? ? ?nplanes = 1;
>> >> + ? ? ? ?pal = monoblack_pal;
>> >> + ? ? ? ?break;
>> >> + ? ?default:
>> >> + ? ? ? ?av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");
>> >> + ? ? ? ?return -1;
>> >> + ? ?}
>> >> +
>> >> + ? ?line_bytes = (avctx->width * bpp + 7) >> 3;
>> >> + ? ?line_bytes = (line_bytes + 1) & ~1;
>> >> +
>> >> + ? ?bytestream_put_byte(&buf, 10); ? ? ? ? ? ? ? ? ?// manufacturer
>> >> + ? ?bytestream_put_byte(&buf, 5); ? ? ? ? ? ? ? ? ? // version
>> >> + ? ?bytestream_put_byte(&buf, 1); ? ? ? ? ? ? ? ? ? // encoding
>> >> + ? ?bytestream_put_byte(&buf, bpp); ? ? ? ? ? ? ? ? // bits per pixel per plane
>> >> + ? ?bytestream_put_le16(&buf, 0); ? ? ? ? ? ? ? ? ? // x min
>> >> + ? ?bytestream_put_le16(&buf, 0); ? ? ? ? ? ? ? ? ? // y min
>> >> + ? ?bytestream_put_le16(&buf, avctx->width - 1); ? ?// x max
>> >> + ? ?bytestream_put_le16(&buf, avctx->height - 1); ? // y max
>> >> + ? ?bytestream_put_le16(&buf, 0); ? ? ? ? ? ? ? ? ? // horizontal DPI
>> >> + ? ?bytestream_put_le16(&buf, 0); ? ? ? ? ? ? ? ? ? // vertical DPI
>> >> + ? ?for (i = 0; i < 16; i++)
>> >> + ? ? ? ?bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)
>> >> + ? ?bytestream_put_byte(&buf, 0); ? ? ? ? ? ? ? ? ? // reserved
>> >> + ? ?bytestream_put_byte(&buf, nplanes); ? ? ? ? ? ? // number of planes
>> >> + ? ?bytestream_put_le16(&buf, line_bytes); ? ? ? ? ?// scanline plane size in bytes
>> >> +
>> >> + ? ?while (buf - buf_start < 128)
>> >> + ? ? ? ?*buf++= 0;
>> >> +
>> >> + ? ?plane = av_mallocz(line_bytes);
>> >> + ? ?src = pict->data[0];
>> >> + ? ?src_line_size = (avctx->width * nplanes * bpp + 7) >> 3;
>> >> +
>> >> + ? ?for (y = 0; y < avctx->height; y++) {
>> >> + ? ? ? ?for (p = 0; p < nplanes; p++) {
>> >> + ? ? ? ? ? ?for (i = p, j = 0; i < src_line_size; i += nplanes, j++) {
>> >> + ? ? ? ? ? ? ? ?plane[j] = src[i];
>> >> + ? ? ? ? ? ?}
>> >> + ? ? ? ? ? ?if ((written = pcx_rle_encode(buf, buf_end - buf,
>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?plane, line_bytes)) < 0) {
>> >> + ? ? ? ? ? ? ? ?av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
>> >> + ? ? ? ? ? ? ? ?av_free(plane);
>> >> + ? ? ? ? ? ? ? ?return -1;
>> >> + ? ? ? ? ? ?}
>> >
>> > i think plane could be avoided by passing nplanes into pcx_rle_encode()
>> > and i think that wouldnt make pcx_rle_encode uglier ...
>> >
>>
>> Ok, reworked to move the plane handling into pcx_rle_encode().
>
> [...]
>> +static int pcx_rle_encode( ? ? ?uint8_t *dst, int dst_size,
>> + ? ? ? ? ? ? ? ? ? ? ? ? ?const uint8_t *src, int src_plane_size, int nplanes)
>> +{
>> + ? ?int p;
>> + ? ?const uint8_t *dst_start = dst;
>> +
>> + ? ?// check worst-case upper bound on dst_size
>> + ? ?if (dst_size < 2LL * src_plane_size * nplanes || src_plane_size <= 0)
>> + ? ? ? ?return -1;
>> +
>> + ? ?for (p = 0; p < nplanes; p++) {
>
> i would have expected that to be outside the function but thats not
> a request to change it, just a note
>

Well, if support is ever added for 2 or 4 bits per pixel, the user
won't be able to do something like "pass the address of the buffer +
some bits" as the start of the plane to the encoder... it only works
currently since the plane support is only used for bpp == 8 where
picking out a value from a particular plane is just a matter of byte
addressing, not the more complicated splitting that would be required
for < 8 bpp.

In any case, I find it a little distasteful to put any of the plane
stuff in the RLE encoder; it seems a little "impure" - but I guess it
is worth it to eliminate the swizzling in an extra buffer (plus I
doubt anything else uses PCX-style RLE encoding anyway, so this
function probably won't get reused).

>
>> + ? ? ? ?int i, count = 1;
>> + ? ? ? ?const uint8_t *src_plane = src + p;
>> + ? ? ? ?uint8_t prev = *src_plane;
>> + ? ? ? ?src_plane += nplanes;
>> +
>> + ? ? ? ?for (i = 1; ; i++, src_plane += nplanes) {
>> + ? ? ? ? ? ?if (i != src_plane_size && *src_plane == prev && count < 0x3F) {
>> + ? ? ? ? ? ? ? ?// current byte is same as prev
>> + ? ? ? ? ? ? ? ?++count;
>> + ? ? ? ? ? ?} else {
>> + ? ? ? ? ? ? ? ?// output prev * count
>> + ? ? ? ? ? ? ? ?if (count != 1 || prev >= 0xC0)
>> + ? ? ? ? ? ? ? ? ? ?*dst++ = 0xC0 | count;
>> + ? ? ? ? ? ? ? ?*dst++ = prev;
>> +
>> + ? ? ? ? ? ? ? ?if (i == src_plane_size)
>> + ? ? ? ? ? ? ? ? ? ?break;
>> +
>> + ? ? ? ? ? ? ? ?// start new run
>> + ? ? ? ? ? ? ? ?count = 1;
>> + ? ? ? ? ? ? ? ?prev = *src_plane;
>> + ? ? ? ? ? ?}
>> + ? ? ? ?}
>
> the number of variables in this loop can be reduced
> a changed src_plane_size can be checked against src_plane thus making
> i unneeded
>

Reworked... is this what you had in mind?

> [...]
> --
> Michael ? ? GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>

Thanks,
-- Daniel Verkamp
-------------- next part --------------
>From 045ffeecb4aedb57f42528ce737d6a83d74cb3f6 Mon Sep 17 00:00:00 2001
From: Daniel Verkamp <daniel at drv.nu>
Date: Sat, 14 Mar 2009 14:41:56 -0500
Subject: [PATCH] Add PCX encoder

---
 Changelog              |    1 +
 doc/general.texi       |    2 +-
 libavcodec/Makefile    |    1 +
 libavcodec/allcodecs.c |    2 +-
 libavcodec/pcxenc.c    |  206 ++++++++++++++++++++++++++++++++++++++++++++++++
 libavformat/img2.c     |    2 +-
 6 files changed, 211 insertions(+), 3 deletions(-)
 create mode 100644 libavcodec/pcxenc.c

diff --git a/Changelog b/Changelog
index 7538ea6..0d2a16e 100644
--- a/Changelog
+++ b/Changelog
@@ -4,6 +4,7 @@ version <next>:
 - deprecated vhook subsystem removed
 - deprecated old scaler removed
 - VQF demuxer
+- PCX encoder
 
 
 
diff --git a/doc/general.texi b/doc/general.texi
index 602d5f4..dac84f9 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -250,7 +250,7 @@ following image formats are supported:
     @tab PAM is a PNM extension with alpha support.
 @item PBM          @tab X @tab X
     @tab Portable BitMap image
- at item PCX          @tab   @tab X
+ at item PCX          @tab X @tab X
     @tab PC Paintbrush
 @item PGM          @tab X @tab X
     @tab Portable GrayMap image
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 13415fc..8175fc5 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -159,6 +159,7 @@ OBJS-$(CONFIG_NUV_DECODER)             += nuv.o rtjpeg.o
 OBJS-$(CONFIG_PAM_ENCODER)             += pnmenc.o pnm.o
 OBJS-$(CONFIG_PBM_ENCODER)             += pnmenc.o pnm.o
 OBJS-$(CONFIG_PCX_DECODER)             += pcx.o
+OBJS-$(CONFIG_PCX_ENCODER)             += pcxenc.o
 OBJS-$(CONFIG_PGM_ENCODER)             += pnmenc.o pnm.o
 OBJS-$(CONFIG_PGMYUV_ENCODER)          += pnmenc.o pnm.o
 OBJS-$(CONFIG_PNG_DECODER)             += png.o pngdec.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index b024e01..bc37401 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -127,7 +127,7 @@ void avcodec_register_all(void)
     REGISTER_DECODER (NUV, nuv);
     REGISTER_ENCODER (PAM, pam);
     REGISTER_ENCODER (PBM, pbm);
-    REGISTER_DECODER (PCX, pcx);
+    REGISTER_ENCDEC  (PCX, pcx);
     REGISTER_ENCODER (PGM, pgm);
     REGISTER_ENCODER (PGMYUV, pgmyuv);
     REGISTER_ENCDEC  (PNG, png);
diff --git a/libavcodec/pcxenc.c b/libavcodec/pcxenc.c
new file mode 100644
index 0000000..36f7d1d
--- /dev/null
+++ b/libavcodec/pcxenc.c
@@ -0,0 +1,206 @@
+/*
+ * PC Paintbrush PCX (.pcx) image encoder
+ * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * PCX image encoder
+ * @file libavcodec/pcxenc.c
+ * @author Daniel Verkamp
+ * @sa http://www.qzx.com/pc-gpe/pcx.txt
+ */
+
+#include "avcodec.h"
+#include "bytestream.h"
+
+typedef struct PCXContext {
+    AVFrame picture;
+} PCXContext;
+
+static const uint32_t monoblack_pal[] = { 0x000000, 0xFFFFFF };
+
+static av_cold int pcx_encode_init(AVCodecContext *avctx)
+{
+    PCXContext *s = avctx->priv_data;
+
+    avcodec_get_frame_defaults(&s->picture);
+    avctx->coded_frame = &s->picture;
+
+    return 0;
+}
+
+/**
+ * PCX run-length encoder
+ * @param dst output buffer
+ * @param dst_size size of output buffer
+ * @param src input buffer
+ * @param src_plane_size size of one plane of input buffer in bytes
+ * @param nplanes number of planes in input buffer
+ * @return number of bytes written to dst or -1 on error
+ * @bug will not work for nplanes != 1 && bpp != 8
+ */
+static int pcx_rle_encode(      uint8_t *dst, int dst_size,
+                          const uint8_t *src, int src_plane_size, int nplanes)
+{
+    int p;
+    const uint8_t *dst_start = dst;
+
+    // check worst-case upper bound on dst_size
+    if (dst_size < 2LL * src_plane_size * nplanes || src_plane_size <= 0)
+        return -1;
+
+    for (p = 0; p < nplanes; p++) {
+        int count = 1;
+        const uint8_t *src_plane = src + p;
+        const uint8_t *src_plane_end = src_plane + src_plane_size * nplanes;
+        uint8_t prev = *src_plane;
+        src_plane += nplanes;
+
+        for (; ; src_plane += nplanes) {
+            if (src_plane < src_plane_end && *src_plane == prev && count < 0x3F) {
+                // current byte is same as prev
+                ++count;
+            } else {
+                // output prev * count
+                if (count != 1 || prev >= 0xC0)
+                    *dst++ = 0xC0 | count;
+                *dst++ = prev;
+
+                if (src_plane == src_plane_end)
+                    break;
+
+                // start new run
+                count = 1;
+                prev = *src_plane;
+            }
+        }
+    }
+
+    return dst - dst_start;
+}
+
+static int pcx_encode_frame(AVCodecContext *avctx,
+                            unsigned char *buf, int buf_size, void *data)
+{
+    PCXContext *s = avctx->priv_data;
+    AVFrame *const pict = &s->picture;
+    const uint8_t *buf_start = buf;
+    const uint8_t *buf_end   = buf + buf_size;
+
+    int bpp, nplanes, i, y, line_bytes, written;
+    const uint32_t *pal = NULL;
+    const uint8_t *src;
+
+    *pict = *(AVFrame *)data;
+    pict->pict_type = FF_I_TYPE;
+    pict->key_frame = 1;
+
+    if (avctx->width > 65535 || avctx->height > 65535) {
+        av_log(avctx, AV_LOG_ERROR, "image dimensions do not fit in 16 bits\n");
+        return -1;
+    }
+
+    switch (avctx->pix_fmt) {
+    case PIX_FMT_RGB24:
+        bpp = 8;
+        nplanes = 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:
+        bpp = 8;
+        nplanes = 1;
+        pal = (uint32_t *)pict->data[1];
+        break;
+    case PIX_FMT_MONOBLACK:
+        bpp = 1;
+        nplanes = 1;
+        pal = monoblack_pal;
+        break;
+    default:
+        av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");
+        return -1;
+    }
+
+    line_bytes = (avctx->width * bpp + 7) >> 3;
+    line_bytes = (line_bytes + 1) & ~1;
+
+    bytestream_put_byte(&buf, 10);                  // manufacturer
+    bytestream_put_byte(&buf, 5);                   // version
+    bytestream_put_byte(&buf, 1);                   // encoding
+    bytestream_put_byte(&buf, bpp);                 // bits per pixel per plane
+    bytestream_put_le16(&buf, 0);                   // x min
+    bytestream_put_le16(&buf, 0);                   // y min
+    bytestream_put_le16(&buf, avctx->width - 1);    // x max
+    bytestream_put_le16(&buf, avctx->height - 1);   // y max
+    bytestream_put_le16(&buf, 0);                   // horizontal DPI
+    bytestream_put_le16(&buf, 0);                   // vertical DPI
+    for (i = 0; i < 16; i++)
+        bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)
+    bytestream_put_byte(&buf, 0);                   // reserved
+    bytestream_put_byte(&buf, nplanes);             // number of planes
+    bytestream_put_le16(&buf, line_bytes);          // scanline plane size in bytes
+
+    while (buf - buf_start < 128)
+        *buf++= 0;
+
+    src = pict->data[0];
+
+    for (y = 0; y < avctx->height; y++) {
+        if ((written = pcx_rle_encode(buf, buf_end - buf,
+                                      src, line_bytes, nplanes)) < 0) {
+            av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
+            return -1;
+        }
+        buf += written;
+        src += pict->linesize[0];
+    }
+
+    if (nplanes == 1 && bpp == 8) {
+        if (buf_end - buf < 257) {
+            av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
+            return -1;
+        }
+        bytestream_put_byte(&buf, 12);
+        for (i = 0; i < 256; i++) {
+            bytestream_put_be24(&buf, pal[i]);
+        }
+    }
+
+    return buf - buf_start;
+}
+
+AVCodec pcx_encoder = {
+    "pcx",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_PCX,
+    sizeof(PCXContext),
+    pcx_encode_init,
+    pcx_encode_frame,
+    NULL,
+    .pix_fmts = (enum PixelFormat[]){
+        PIX_FMT_RGB24,
+        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("PC Paintbrush PCX image"),
+};
diff --git a/libavformat/img2.c b/libavformat/img2.c
index 113f431..48f3dfc 100644
--- a/libavformat/img2.c
+++ b/libavformat/img2.c
@@ -428,7 +428,7 @@ AVOutputFormat image2_muxer = {
     "image2",
     NULL_IF_CONFIG_SMALL("image2 sequence"),
     "",
-    "bmp,jpeg,jpg,ljpg,pam,pbm,pgm,pgmyuv,png,ppm,sgi,tif,tiff,jp2",
+    "bmp,jpeg,jpg,ljpg,pam,pbm,pcx,pgm,pgmyuv,png,ppm,sgi,tif,tiff,jp2",
     sizeof(VideoData),
     CODEC_ID_NONE,
     CODEC_ID_MJPEG,
-- 
1.6.2



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