diff mbox series

[FFmpeg-devel,RFC] libavcodec/jpeg2000_parser: Add jpeg2000 parser

Message ID 20200418193002.15752-1-gautamramk@gmail.com
State Superseded
Headers show
Series [FFmpeg-devel,RFC] libavcodec/jpeg2000_parser: Add jpeg2000 parser
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Commit Message

Gautam Ramakrishnan April 18, 2020, 7:30 p.m. UTC
From: Gautam Ramakrishnan <gautamramk@gmail.com>

I have attempted to write a JPEG2000 Parser. Need
help on testing the code and some tips on how to
document this code. The variable names are also
a bit hard to understand. Would appreciate some
tips. The sample from #7445 seems to get decoded
now.
---
 libavcodec/Makefile          |   1 +
 libavcodec/jpeg2000_parser.c | 148 +++++++++++++++++++++++++++++++++++
 libavcodec/parsers.c         |   1 +
 3 files changed, 150 insertions(+)
 create mode 100644 libavcodec/jpeg2000_parser.c

Comments

Carl Eugen Hoyos April 19, 2020, 2:50 a.m. UTC | #1
Am Sa., 18. Apr. 2020 um 21:54 Uhr schrieb <gautamramk@gmail.com>:
>
> From: Gautam Ramakrishnan <gautamramk@gmail.com>
>
> I have attempted to write a JPEG2000 Parser.

Does it work both for format j2k and jp2 as written
by FFmpeg's encoder?

Carl Eugen
Michael Niedermayer April 19, 2020, 9:47 a.m. UTC | #2
On Sun, Apr 19, 2020 at 01:00:02AM +0530, gautamramk@gmail.com wrote:
> From: Gautam Ramakrishnan <gautamramk@gmail.com>
> 
> I have attempted to write a JPEG2000 Parser. Need
> help on testing the code and some tips on how to
> document this code. The variable names are also
> a bit hard to understand. Would appreciate some
> tips. The sample from #7445 seems to get decoded
> now.
> ---
>  libavcodec/Makefile          |   1 +
>  libavcodec/jpeg2000_parser.c | 148 +++++++++++++++++++++++++++++++++++
>  libavcodec/parsers.c         |   1 +
>  3 files changed, 150 insertions(+)
>  create mode 100644 libavcodec/jpeg2000_parser.c

breaks some refernce j2k files

./ffplay j2kreffile/p0_03.j2k

this is a black picture afterwards but showed something before

thx

[...]
Gautam Ramakrishnan April 19, 2020, 11:44 a.m. UTC | #3
On Sun, Apr 19, 2020 at 8:20 AM Carl Eugen Hoyos <ceffmpeg@gmail.com> wrote:
>
> Am Sa., 18. Apr. 2020 um 21:54 Uhr schrieb <gautamramk@gmail.com>:
> >
> > From: Gautam Ramakrishnan <gautamramk@gmail.com>
> >
> > I have attempted to write a JPEG2000 Parser.
>
> Does it work both for format j2k and jp2 as written
> by FFmpeg's encoder?
>
I have tried to make it work for both. j2k files have only
the codestream content. The parser attempts to parse
full files or just codestreams. So if the stream has a
a jp2 file and a j2k codestream, it should work.
> Carl Eugen
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Gautam Ramakrishnan April 19, 2020, 11:45 a.m. UTC | #4
On Sun, Apr 19, 2020 at 3:17 PM Michael Niedermayer
<michael@niedermayer.cc> wrote:
>
> On Sun, Apr 19, 2020 at 01:00:02AM +0530, gautamramk@gmail.com wrote:
> > From: Gautam Ramakrishnan <gautamramk@gmail.com>
> >
> > I have attempted to write a JPEG2000 Parser. Need
> > help on testing the code and some tips on how to
> > document this code. The variable names are also
> > a bit hard to understand. Would appreciate some
> > tips. The sample from #7445 seems to get decoded
> > now.
> > ---
> >  libavcodec/Makefile          |   1 +
> >  libavcodec/jpeg2000_parser.c | 148 +++++++++++++++++++++++++++++++++++
> >  libavcodec/parsers.c         |   1 +
> >  3 files changed, 150 insertions(+)
> >  create mode 100644 libavcodec/jpeg2000_parser.c
>
> breaks some refernce j2k files
>
> ./ffplay j2kreffile/p0_03.j2k
>
> this is a black picture afterwards but showed something before
>
Thanks Michael, I'll look into this.
> thx
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> Rewriting code that is poorly written but fully understood is good.
> Rewriting code that one doesnt understand is a sign that one is less smart
> then the original author, trying to rewrite it will not make it better.
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
diff mbox series

Patch

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 88944d9a3a..dedd7a0429 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -1062,6 +1062,7 @@  OBJS-$(CONFIG_H261_PARSER)             += h261_parser.o
 OBJS-$(CONFIG_H263_PARSER)             += h263_parser.o
 OBJS-$(CONFIG_H264_PARSER)             += h264_parser.o h264_sei.o h264data.o
 OBJS-$(CONFIG_HEVC_PARSER)             += hevc_parser.o hevc_data.o
+OBJS-$(CONFIG_JPEG2000_PARSER)         += jpeg2000_parser.o
 OBJS-$(CONFIG_MJPEG_PARSER)            += mjpeg_parser.o
 OBJS-$(CONFIG_MLP_PARSER)              += mlp_parse.o mlp_parser.o mlp.o
 OBJS-$(CONFIG_MPEG4VIDEO_PARSER)       += mpeg4video_parser.o h263.o \
diff --git a/libavcodec/jpeg2000_parser.c b/libavcodec/jpeg2000_parser.c
new file mode 100644
index 0000000000..e172c5a9c9
--- /dev/null
+++ b/libavcodec/jpeg2000_parser.c
@@ -0,0 +1,148 @@ 
+/*
+ * JPEG2000 parser
+ * Copyright (c) 2000, 2001 Fabrice Bellard
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * JPEG2000 parser.
+ */
+
+#include "parser.h"
+
+typedef struct JPEG2000ParserContext{
+    ParseContext pc;
+    uint64_t bytes_read;
+    uint64_t fheader_state;
+    uint8_t fheader_read;
+    uint8_t frame_type; // 1 if file, 2 if codestream
+    uint8_t reading_file_header;
+    uint8_t skipped_codestream;
+    uint8_t codestream_frame_end;
+}JPEG2000ParserContext;
+
+static inline void reset_context(JPEG2000ParserContext *m)
+{
+    ParseContext *pc = &m->pc;
+
+    pc->frame_start_found= 0;
+    pc->state = 0;
+    m->bytes_read = 0;
+    m->frame_type = 0;
+    m->skipped_codestream = 0;
+    m->fheader_read = 0;
+    m->fheader_state = 0;
+    m->reading_file_header = 0;
+    m->codestream_frame_end = 0;
+}
+/**
+ * Find the end of the current frame in the bitstream.
+ * @return the position of the first byte of the next frame, or -1
+ */
+static int find_frame_end(JPEG2000ParserContext *m, const uint8_t *buf, int buf_size)
+{
+    ParseContext *pc= &m->pc;
+    int i;
+    uint32_t state;
+    state= pc->state;
+
+    if (buf_size == 0) {
+        return 0;
+    }
+
+    for (i = 0; i < buf_size; i++) {
+        state = state << 8 | buf[i];
+        m->bytes_read++;
+        if (m->codestream_frame_end) {
+            reset_context(m);
+            return i;
+        }
+        if (m->reading_file_header) {
+            m->fheader_state = m->fheader_state << 8 | buf[i];
+            m->fheader_read++;
+            if (m->fheader_read == 8) {
+                if (m->fheader_state == 0x6A5020200D0A870A) {
+                    if (pc->frame_start_found) {
+                        pc->frame_start_found = 0;
+                        reset_context(m);
+                        return i - 11;
+                    } else {
+                        pc->frame_start_found = 1;
+                        m->frame_type = 1;
+                    }
+                }
+                m->reading_file_header = 0;
+                m->fheader_read = 0;
+            }
+        }
+        if (state == 0x0000000C && m->bytes_read >= 3) {
+            m->reading_file_header = 1;
+        } else if ((state & 0xFFFF) == 0xFF4F) {
+            if (!pc->frame_start_found) {
+                pc->frame_start_found = 1;
+                m->frame_type = 2;
+            } else if (pc->frame_start_found && m->frame_type == 1 && m->skipped_codestream) {
+                reset_context(m);
+                return i - 1;
+            }
+        } else if ((state & 0xFFFF) == 0xFFD9) {
+            if (pc->frame_start_found && m->frame_type == 1) {
+                m->skipped_codestream = 1;
+            } else if (pc->frame_start_found && m->frame_type == 2) {
+                m->codestream_frame_end = 1;
+            }
+        }
+    }
+
+    pc->state= state;
+    return END_NOT_FOUND;
+}
+
+static int jpeg2000_parse(AVCodecParserContext *s,
+                          AVCodecContext *avctx,
+                          const uint8_t **poutbuf, int *poutbuf_size,
+                          const uint8_t *buf, int buf_size)
+{
+    JPEG2000ParserContext *m = s->priv_data;
+    ParseContext *pc = &m->pc;
+    int next;
+
+    if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
+        next= buf_size;
+    }else{
+        next= find_frame_end(m, buf, buf_size);
+
+        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
+            *poutbuf = NULL;
+            *poutbuf_size = 0;
+            return buf_size;
+        }
+    }
+
+    *poutbuf = buf;
+    *poutbuf_size = buf_size;
+    return next;
+}
+
+AVCodecParser ff_jpeg2000_parser = {
+    .codec_ids      = { AV_CODEC_ID_JPEG2000 },
+    .priv_data_size = sizeof(JPEG2000ParserContext),
+    .parser_parse   = jpeg2000_parse,
+    .parser_close   = ff_parse_close,
+};
\ No newline at end of file
diff --git a/libavcodec/parsers.c b/libavcodec/parsers.c
index 9fbf182594..7d75cea830 100644
--- a/libavcodec/parsers.c
+++ b/libavcodec/parsers.c
@@ -48,6 +48,7 @@  extern AVCodecParser ff_h261_parser;
 extern AVCodecParser ff_h263_parser;
 extern AVCodecParser ff_h264_parser;
 extern AVCodecParser ff_hevc_parser;
+extern AVCodecParser ff_jpeg2000_parser;
 extern AVCodecParser ff_mjpeg_parser;
 extern AVCodecParser ff_mlp_parser;
 extern AVCodecParser ff_mpeg4video_parser;