[FFmpeg-devel] libavcodec: r12b decoder

Dennis Fleurbaaij mail at dennisfleurbaaij.com
Mon Jun 7 23:10:38 EEST 2021


Thanks for the review Andreas!

I've addressed all your concerns besides the "& in the define", I didn't
know that the binary AND is implicit in this situation, any link for this?
Even if it is, I just find it much more pleasing to see the & there
somehow, is there some leniency for personal preference?

Revised patch attached.

Kind regards,
Dennis Fleurbaaij


On Mon, Jun 7, 2021 at 12:59 PM Andreas Rheinhardt <
andreas.rheinhardt at outlook.com> wrote:

> Dennis Fleurbaaij:
> > Pulled master and re-applied to resolve version update conflict
> >
> > Kind regards,
> > Dennis Fleurbaaij
> >
> >
> >
> > +    if (avctx->width % PIXELS_PER_BLOCK != 0) {
> > +        av_log(avctx, AV_LOG_ERROR, "image width not modulo 8\n");
> > +        return AVERROR_INVALIDDATA;
> > +    }
> > +
> > +    AVFrame *pic = data;
> > +    pic->pict_type = AV_PICTURE_TYPE_I;
> > +    pic->key_frame = 1;
> > +
>
> This (and other declarations below) should give statement-before
> declaration warnings (FFmpeg still uses the C90 convention that all
> declarations have to be at the top of each block.
>
> > +    const uint8_t* src = (const uint8_t *)avpkt->data;
>
> Unnecessary cast (adding const is safe and doesn't need a cast).
>
> >
> > +            #define GET_F0(word, byte) ((GET_FF(word, byte) & 0xF0) >>
> 4)
>
> The & is unnecessary, but the compiler will probably figure this out on
> its own.
>
> >
> > +#if CONFIG_R12B_DECODER
> > +const AVCodec ff_r12b_decoder = {
> > +    .name           = "r12b",
> > +    .long_name      = NULL_IF_CONFIG_SMALL("Uncompressed RGB 12-bit 8px
> in 36B"),
> > +    .type           = AVMEDIA_TYPE_VIDEO,
> > +    .id             = AV_CODEC_ID_R12B,
> > +    .init           = decode_init,
> > +    .decode         = decode_frame,
> > +    .capabilities   = AV_CODEC_CAP_DR1,
> > +    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
> > +};
> > +#endif
>
> The #if is unnecessary as r12bdec.c will only get compiled if
> CONFIG_R12B_DECODER is true.
>
> - Andreas
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
>
-------------- next part --------------
From 34f967772e3c8378ac3dd1f55a293e478dcc919c Mon Sep 17 00:00:00 2001
From: Dennis Fleurbaaij <mail at dennisfleurbaaij.com>
Date: Mon, 7 Jun 2021 21:53:42 +0200
Subject: [PATCH] libavcodec: r12b decoder added

R12B is a format used by BlackMagic DeckLink cards, it is
a big-endian 12bpp RGB format which packs 8 pixels into 36
bytes.

Signed-off-by: Dennis Fleurbaaij <mail at dennisfleurbaaij.com>
---
 Changelog               |   1 +
 libavcodec/Makefile     |   1 +
 libavcodec/allcodecs.c  |   1 +
 libavcodec/codec_desc.c |   7 ++
 libavcodec/codec_id.h   |   1 +
 libavcodec/r12bdec.c    | 139 ++++++++++++++++++++++++++++++++++++++++
 libavcodec/version.h    |   4 +-
 libavformat/riff.c      |   1 +
 8 files changed, 153 insertions(+), 2 deletions(-)
 create mode 100644 libavcodec/r12bdec.c

diff --git a/Changelog b/Changelog
index b9d5188cf6..d0717072eb 100644
--- a/Changelog
+++ b/Changelog
@@ -7,6 +7,7 @@ version <next>:
 - ADPCM IMA Acorn Replay decoder
 - Argonaut Games CVG demuxer
 - Argonaut Games CVG muxer
+- r12b decoder
 
 
 version 4.4:
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 4fa8d7ab10..cfef9d57ff 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -575,6 +575,7 @@ OBJS-$(CONFIG_QTRLE_ENCODER)           += qtrleenc.o
 OBJS-$(CONFIG_R10K_DECODER)            += r210dec.o
 OBJS-$(CONFIG_R10K_ENCODER)            += r210enc.o
 OBJS-$(CONFIG_R210_DECODER)            += r210dec.o
+OBJS-$(CONFIG_R12B_DECODER)            += r12bdec.o
 OBJS-$(CONFIG_R210_ENCODER)            += r210enc.o
 OBJS-$(CONFIG_RA_144_DECODER)          += ra144dec.o ra144.o celp_filters.o
 OBJS-$(CONFIG_RA_144_ENCODER)          += ra144enc.o ra144.o celp_filters.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 623db2a9fa..8db7e730a6 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -266,6 +266,7 @@ extern const AVCodec ff_qtrle_encoder;
 extern const AVCodec ff_qtrle_decoder;
 extern const AVCodec ff_r10k_encoder;
 extern const AVCodec ff_r10k_decoder;
+extern const AVCodec ff_r12b_decoder;
 extern const AVCodec ff_r210_encoder;
 extern const AVCodec ff_r210_decoder;
 extern const AVCodec ff_rasc_decoder;
diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
index 35527dcc37..ef58d73576 100644
--- a/libavcodec/codec_desc.c
+++ b/libavcodec/codec_desc.c
@@ -1856,6 +1856,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .long_name = NULL_IF_CONFIG_SMALL("Digital Pictures SGA Video"),
         .props     = AV_CODEC_PROP_LOSSY,
     },
+    {
+        .id        = AV_CODEC_ID_R12B,
+        .type      = AVMEDIA_TYPE_VIDEO,
+        .name      = "r12b",
+        .long_name = NULL_IF_CONFIG_SMALL("Uncompressed RGB 12-bit 8px in 36B"),
+        .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSLESS,
+    },
 
     /* various PCM "codecs" */
     {
diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
index 83e1dbb4b3..ecfdbc46c0 100644
--- a/libavcodec/codec_id.h
+++ b/libavcodec/codec_id.h
@@ -306,6 +306,7 @@ enum AVCodecID {
     AV_CODEC_ID_CRI,
     AV_CODEC_ID_SIMBIOSIS_IMX,
     AV_CODEC_ID_SGA_VIDEO,
+    AV_CODEC_ID_R12B,
 
     /* various PCM "codecs" */
     AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs
diff --git a/libavcodec/r12bdec.c b/libavcodec/r12bdec.c
new file mode 100644
index 0000000000..4f9c085ecd
--- /dev/null
+++ b/libavcodec/r12bdec.c
@@ -0,0 +1,139 @@
+/*
+ * r12b decoder
+ *
+ * Copyright (c) 2021 Dennis Fleurbaaij <mail at dennisfleurbaaij.com>
+ *
+ * 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 "libavutil/bswap.h"
+#include "libavutil/common.h"
+
+#define WORDS_PER_BLOCK 9
+#define PIXELS_PER_BLOCK 8
+#define BYTES_PER_BLOCK 36
+
+static av_cold int decode_init(AVCodecContext *avctx)
+{
+    avctx->pix_fmt = AV_PIX_FMT_GBRP12LE;
+    avctx->bits_per_raw_sample = 12;
+
+    return 0;
+}
+
+static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
+                        AVPacket *avpkt)
+{
+    int ret, h, w;
+    uint8_t *g_line, *b_line, *r_line;
+    uint16_t *g_dst, *b_dst, *r_dst;
+
+    AVFrame *pic = data;
+    const uint8_t* src = avpkt->data;
+    const int blocks_per_line = avctx->width / PIXELS_PER_BLOCK;
+
+    if (avctx->width % PIXELS_PER_BLOCK != 0) {
+        av_log(avctx, AV_LOG_ERROR, "image width not modulo 8\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    pic->pict_type = AV_PICTURE_TYPE_I;
+    pic->key_frame = 1;
+
+    if ((ret = ff_get_buffer(avctx, pic, 0)) < 0)
+        return ret;
+
+    g_line = pic->data[0];
+    b_line = pic->data[1];
+    r_line = pic->data[2];
+
+    for (h = 0; h < avctx->height; h++) {
+        g_dst = (uint16_t *)g_line;
+        b_dst = (uint16_t *)b_line;
+        r_dst = (uint16_t *)r_line;
+
+        for (w = 0; w < blocks_per_line; w++) {
+
+            // This is an encoding from the table on page 213 of the BlackMagic
+            // Decklink SDK pdf, version 12.0. Few helper defines to directly link
+            // the naming in the doc to the code.
+
+            #define GET_FF(word, byte) (*(src + ((word * 4) + byte)))
+            #define GET_0F(word, byte) (GET_FF(word, byte) & 0x0F)
+            #define GET_F0(word, byte) ((GET_FF(word, byte) & 0xF0) >> 4)
+            #define PUT(dst, pixel) (*(dst + pixel))
+
+            PUT(b_dst, 0) = GET_FF(0, 0) | GET_0F(1, 3) << 8;
+            PUT(g_dst, 0) = GET_F0(0, 2) | GET_FF(0, 1) << 4;
+            PUT(r_dst, 0) = GET_FF(0, 3) | GET_0F(0, 2) << 8;
+
+            PUT(b_dst, 1) = GET_F0(1, 0) | GET_FF(2, 3) << 4;
+            PUT(g_dst, 1) = GET_FF(1, 1) | GET_0F(1, 0) << 8;
+            PUT(r_dst, 1) = GET_F0(1, 3) | GET_FF(1, 2) << 4;
+
+            PUT(b_dst, 2) = GET_FF(3, 3) | GET_0F(3, 2) << 8;
+            PUT(g_dst, 2) = GET_F0(2, 1) | GET_FF(2, 0) << 4;
+            PUT(r_dst, 2) = GET_FF(2, 2) | GET_0F(2, 1) << 8;
+
+            PUT(b_dst, 3) = GET_F0(4, 3) | GET_FF(4, 2) << 4;
+            PUT(g_dst, 3) = GET_FF(3, 0) | GET_0F(4, 3) << 8;
+            PUT(r_dst, 3) = GET_F0(3, 2) | GET_FF(3, 1) << 4;
+
+            PUT(b_dst, 4) = GET_FF(5, 2) | GET_0F(5, 1) << 8;
+            PUT(g_dst, 4) = GET_F0(4, 0) | GET_FF(5, 3) << 4;
+            PUT(r_dst, 4) = GET_FF(4, 1) | GET_0F(4, 0) << 8;
+
+            PUT(b_dst, 5) = GET_F0(6, 2) | GET_FF(6, 1) << 4;
+            PUT(g_dst, 5) = GET_FF(6, 3) | GET_0F(6, 2) << 8;
+            PUT(r_dst, 5) = GET_F0(5, 1) | GET_FF(5, 0) << 4;
+
+            PUT(b_dst, 6) = GET_FF(7, 1) | GET_0F(7, 0) << 8;
+            PUT(g_dst, 6) = GET_F0(7, 3) | GET_FF(7, 2) << 4;
+            PUT(r_dst, 6) = GET_FF(6, 0) | GET_0F(7, 3) << 8;
+
+            PUT(b_dst, 7) = GET_F0(8, 1) | GET_FF(8, 0) << 4;
+            PUT(g_dst, 7) = GET_FF(8, 2) | GET_0F(8, 1) << 8;
+            PUT(r_dst, 7) = GET_F0(7, 0) | GET_FF(8, 3) << 4;
+
+            src += BYTES_PER_BLOCK;
+            b_dst += PIXELS_PER_BLOCK;
+            g_dst += PIXELS_PER_BLOCK;
+            r_dst += PIXELS_PER_BLOCK;
+        }
+
+        g_line += pic->linesize[0];
+        b_line += pic->linesize[1];
+        r_line += pic->linesize[2];
+    }
+
+    *got_frame = 1;
+
+    return avpkt->size;
+}
+
+const AVCodec ff_r12b_decoder = {
+    .name           = "r12b",
+    .long_name      = NULL_IF_CONFIG_SMALL("Uncompressed RGB 12-bit 8px in 36B"),
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_R12B,
+    .init           = decode_init,
+    .decode         = decode_frame,
+    .capabilities   = AV_CODEC_CAP_DR1,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
+};
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 5b1e9e77f3..1288cecebe 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -28,8 +28,8 @@
 #include "libavutil/version.h"
 
 #define LIBAVCODEC_VERSION_MAJOR  59
-#define LIBAVCODEC_VERSION_MINOR   1
-#define LIBAVCODEC_VERSION_MICRO 101
+#define LIBAVCODEC_VERSION_MINOR   2
+#define LIBAVCODEC_VERSION_MICRO 100
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \
diff --git a/libavformat/riff.c b/libavformat/riff.c
index 270ff7c024..6e303f59ff 100644
--- a/libavformat/riff.c
+++ b/libavformat/riff.c
@@ -295,6 +295,7 @@ const AVCodecTag ff_codec_bmp_tags[] = {
     { AV_CODEC_ID_FRWU,         MKTAG('F', 'R', 'W', 'U') },
     { AV_CODEC_ID_R10K,         MKTAG('R', '1', '0', 'k') },
     { AV_CODEC_ID_R210,         MKTAG('r', '2', '1', '0') },
+    { AV_CODEC_ID_R12B,         MKTAG('r', '1', '2', 'b') },
     { AV_CODEC_ID_V210,         MKTAG('v', '2', '1', '0') },
     { AV_CODEC_ID_V210,         MKTAG('C', '2', '1', '0') },
     { AV_CODEC_ID_V308,         MKTAG('v', '3', '0', '8') },
-- 
2.31.1.windows.1



More information about the ffmpeg-devel mailing list