[FFmpeg-devel] [PATCH] libavcodec/pgx: Added pgx decoder

gautamramk at gmail.com gautamramk at gmail.com
Wed Jun 24 21:27:10 EEST 2020


From: Gautam Ramakrishnan <gautamramk at gmail.com>

This patch support to read and decode
pgx files.
---
 libavcodec/Makefile      |   1 +
 libavcodec/allcodecs.c   |   1 +
 libavcodec/codec_id.h    |   1 +
 libavcodec/pgx.h         |  38 +++++++++
 libavcodec/pgxdec.c      | 176 +++++++++++++++++++++++++++++++++++++++
 libavformat/allformats.c |   1 +
 libavformat/img2dec.c    |  11 +++
 7 files changed, 229 insertions(+)
 create mode 100644 libavcodec/pgx.h
 create mode 100644 libavcodec/pgxdec.c

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 5a6ea59715..0198c244e0 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -533,6 +533,7 @@ OBJS-$(CONFIG_PCX_ENCODER)             += pcxenc.o
 OBJS-$(CONFIG_PFM_DECODER)             += pnmdec.o pnm.o
 OBJS-$(CONFIG_PGM_DECODER)             += pnmdec.o pnm.o
 OBJS-$(CONFIG_PGM_ENCODER)             += pnmenc.o
+OBJS-$(CONFIG_PGX_DECODER)             += pgxdec.o
 OBJS-$(CONFIG_PGMYUV_DECODER)          += pnmdec.o pnm.o
 OBJS-$(CONFIG_PGMYUV_ENCODER)          += pnmenc.o
 OBJS-$(CONFIG_PGSSUB_DECODER)          += pgssubdec.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index fa0c08d42e..b0217e6d6a 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -236,6 +236,7 @@ extern AVCodec ff_pcx_decoder;
 extern AVCodec ff_pfm_decoder;
 extern AVCodec ff_pgm_encoder;
 extern AVCodec ff_pgm_decoder;
+extern AVCodec ff_pgx_decoder;
 extern AVCodec ff_pgmyuv_encoder;
 extern AVCodec ff_pgmyuv_decoder;
 extern AVCodec ff_pictor_decoder;
diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
index d885962c9c..027ef21c62 100644
--- a/libavcodec/codec_id.h
+++ b/libavcodec/codec_id.h
@@ -111,6 +111,7 @@ enum AVCodecID {
     AV_CODEC_ID_PPM,
     AV_CODEC_ID_PBM,
     AV_CODEC_ID_PGM,
+    AV_CODEC_ID_PGX,
     AV_CODEC_ID_PGMYUV,
     AV_CODEC_ID_PAM,
     AV_CODEC_ID_FFVHUFF,
diff --git a/libavcodec/pgx.h b/libavcodec/pgx.h
new file mode 100644
index 0000000000..bbe93fafe7
--- /dev/null
+++ b/libavcodec/pgx.h
@@ -0,0 +1,38 @@
+/*
+ * PGX image format
+ * Copyright (c) 2020 Gautam Ramakrishnan
+ *
+ * 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
+ */
+
+#ifndef AVCODEC_PGX_H
+#define AVCODEC_PGX_H
+
+#include "avcodec.h"
+#include "bytestream.h"
+
+typedef struct PGXContext {
+    GetByteContext  g;
+    int depth;
+    int sgnd;
+    int width;
+    int height;
+} PGXContext;
+
+int ff_pgx_decode_header(AVCodecContext *avctx, PGXContext * const s);
+
+#endif /* AVCODEC_PNM_H */
\ No newline at end of file
diff --git a/libavcodec/pgxdec.c b/libavcodec/pgxdec.c
new file mode 100644
index 0000000000..233bf34717
--- /dev/null
+++ b/libavcodec/pgxdec.c
@@ -0,0 +1,176 @@
+/*
+ * PGX image format
+ * Copyright (c) 2020 Gautam Ramakrishnan
+ *
+ * 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
+ */
+
+#include "avcodec.h"
+#include "internal.h"
+#include "pgx.h"
+
+static int pgx_get_number(AVCodecContext *avctx, PGXContext * const s) {
+    char number[10];
+    int i;
+    int ret;
+    number[9] = '\0';
+    for (i = 0; i < 9; i++) {
+        if (!bytestream2_get_bytes_left(&s->g))
+            return AVERROR_INVALIDDATA;
+        number[i] = (char)bytestream2_get_byteu(&s->g);
+        if (number[i] == ' ' || number[i] == 0xA || number[i] == 0xD) {
+            number[i] = '\0';
+            break;
+        } else if (number[i] < '0' || number[i] > '9') {
+            return AVERROR_INVALIDDATA;
+        }
+    }
+    if (i > 9)
+        return AVERROR_INVALIDDATA;
+    ret = (int)strtol(number, NULL, 10);
+    if (ret >= 0)
+        return ret;
+    return AVERROR_INVALIDDATA;
+}
+
+int ff_pgx_decode_header(AVCodecContext *avctx, PGXContext * s)
+{
+    const char *header_start = "PG ML ";
+    int i;
+    int byte;
+    if (bytestream2_get_bytes_left(&s->g) < 13) {
+        return AVERROR_INVALIDDATA;
+    }
+
+    for (i = 0; i < 6; i++) {
+        if (header_start[i] != (char)bytestream2_get_byteu(&s->g)) {
+            return AVERROR_INVALIDDATA;
+        }
+    }
+    byte = bytestream2_peek_byte(&s->g);
+    if (byte == '+') {
+        s->sgnd = 0;
+        bytestream2_skip(&s->g, 1);
+    } else if (byte == '-') {
+        s->sgnd = 1;
+        bytestream2_skip(&s->g, 1);
+    }
+
+    if (bytestream2_peek_byte(&s->g) == ' ')
+        bytestream2_skip(&s->g, 1);
+    s->depth = pgx_get_number(avctx, s);
+    s->width = pgx_get_number(avctx, s);
+    s->height = pgx_get_number(avctx, s);
+    if (bytestream2_peek_byte(&s->g) == 0xA)
+        bytestream2_skip(&s->g, 1);
+    return 0;
+}
+
+static inline int write_frame_16(AVPacket *avpkt, AVFrame *frame, PGXContext * const s)
+{
+    int i, j;
+    for (i = 0; i < s->height; i++) {
+        uint16_t* line = (uint16_t*)frame->data[0] + i*frame->linesize[0]/2;
+        for (j = 0; j < s->width; j++) {
+            int val;
+            if (s->sgnd) {
+                val = (int16_t)bytestream2_get_be16(&s->g) + (1 << (s->depth - 1));
+                val <<= (16 - s->depth);
+                *(line + j) = val;
+            } else {
+                val = bytestream2_get_be16u(&s->g);
+                val <<= (16 - s->depth);
+                *(line + j) = val;
+            }
+        }
+        line += frame->linesize[0]/2;
+    }
+    return 0;
+}
+
+static inline int write_frame_8(AVPacket *avpkt, AVFrame *frame, PGXContext * const s)
+{
+    int i, j;
+    for (i = 0; i < s->height; i++) {
+        uint8_t* line = frame->data[0] + i*frame->linesize[0];
+        for (j = 0; j < s->width; j++) {
+            int val;
+            if (s->sgnd) {
+                val = bytestream2_get_byte(&s->g) + (1 << (s->depth - 1));
+                val <<= (8 - s->depth);
+                *(line + j) = val;
+            } else {
+                val = bytestream2_get_byteu(&s->g);
+                val <<= (8 - s->depth);
+                *(line + j) = val;
+            }
+        }
+        line += frame->linesize[0];
+    }
+    return 0;
+}
+
+static int pgx_decode_frame(AVCodecContext *avctx, void *data,
+                            int *got_frame, AVPacket *avpkt)
+{
+    PGXContext * s = avctx->priv_data;
+    AVFrame * const p    = data;
+    int ret;
+    int num_vals;
+    int bpp;
+    bytestream2_init(&s->g, avpkt->data, avpkt->size);
+    if ((ret = ff_pgx_decode_header(avctx, s)) < 0)
+        return ret;
+
+    num_vals = s->width * s->height;
+
+    if (ret = ff_set_dimensions(avctx, s->width, s->height) < 0)
+        return ret;
+
+    if (s->depth <= 8) {
+        avctx->pix_fmt = AV_PIX_FMT_GRAY8;
+        bpp = 8;
+    } else if (s->depth <= 16) {
+        avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
+        bpp = 16;
+    } else {
+        av_log(avctx, AV_LOG_ERROR, "Maximum depth of 16 bits supported.\n");
+        return AVERROR_PATCHWELCOME;
+    }
+
+    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
+        return ret;
+    *got_frame = 1;
+    p->pict_type = AV_PICTURE_TYPE_I;
+    p->key_frame = 1;
+    avctx->bits_per_raw_sample = s->depth;
+    if (bpp == 8)
+        write_frame_8(avpkt, p, s);
+    else if (bpp == 16)
+        write_frame_16(avpkt, p, s);
+    return 0;
+}
+
+AVCodec ff_pgx_decoder = {
+    .name           = "pgx",
+    .long_name      = NULL_IF_CONFIG_SMALL("PGX image"),
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_PGX,
+    .priv_data_size = sizeof(PGXContext),
+    .decode         = pgx_decode_frame,
+    .capabilities   = AV_CODEC_CAP_DR1,
+};
\ No newline at end of file
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 97fd06debb..f8527b1fd4 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -488,6 +488,7 @@ extern AVInputFormat  ff_image_pbm_pipe_demuxer;
 extern AVInputFormat  ff_image_pcx_pipe_demuxer;
 extern AVInputFormat  ff_image_pgmyuv_pipe_demuxer;
 extern AVInputFormat  ff_image_pgm_pipe_demuxer;
+extern AVInputFormat  ff_image_pgx_pipe_demuxer;
 extern AVInputFormat  ff_image_pictor_pipe_demuxer;
 extern AVInputFormat  ff_image_png_pipe_demuxer;
 extern AVInputFormat  ff_image_ppm_pipe_demuxer;
diff --git a/libavformat/img2dec.c b/libavformat/img2dec.c
index ee7ceed08f..43270901ff 100644
--- a/libavformat/img2dec.c
+++ b/libavformat/img2dec.c
@@ -1000,6 +1000,16 @@ static int pgmyuv_probe(const AVProbeData *p) // custom FFmpeg format recognized
     return ret && av_match_ext(p->filename, "pgmyuv") ? ret : 0;
 }
 
+static int pgx_probe(const AVProbeData *p)
+{
+    const uint8_t *b = p->buf;
+    int ret = (AV_RB32(b) & 0xFFFFFF00) == 0x50472000;
+    ret = ret && av_match_ext(p->filename, "pgx");
+    if (ret)
+        return AVPROBE_SCORE_EXTENSION + 1;
+    return 0;
+}
+
 static int ppm_probe(const AVProbeData *p)
 {
     return pnm_magic_check(p, 3) || pnm_magic_check(p, 6) ? pnm_probe(p) : 0;
@@ -1094,6 +1104,7 @@ IMAGEAUTO_DEMUXER(pbm,     AV_CODEC_ID_PBM)
 IMAGEAUTO_DEMUXER(pcx,     AV_CODEC_ID_PCX)
 IMAGEAUTO_DEMUXER(pgm,     AV_CODEC_ID_PGM)
 IMAGEAUTO_DEMUXER(pgmyuv,  AV_CODEC_ID_PGMYUV)
+IMAGEAUTO_DEMUXER(pgx,     AV_CODEC_ID_PGX)
 IMAGEAUTO_DEMUXER(pictor,  AV_CODEC_ID_PICTOR)
 IMAGEAUTO_DEMUXER(png,     AV_CODEC_ID_PNG)
 IMAGEAUTO_DEMUXER(ppm,     AV_CODEC_ID_PPM)
-- 
2.17.1



More information about the ffmpeg-devel mailing list