Additionally, update some documentation with support for APNG
Signed-off-by: Donny Yang <w...@kota.moe>
---
Changelog | 1 +
doc/general.texi | 2 +
libavformat/Makefile | 1 +
libavformat/allformats.c | 2 +-
libavformat/apngenc.c | 249 +++++++++++++++++++++++++++++++++++++++++++++++
libavformat/version.h | 4 +-
6 files changed, 256 insertions(+), 3 deletions(-)
create mode 100644 libavformat/apngenc.c
diff --git a/Changelog b/Changelog
index 109a1b8..a2d4974 100644
--- a/Changelog
+++ b/Changelog
@@ -11,6 +11,7 @@ version <next>:
- nvenc H265 encoder
- Detelecine filter
- Intel QSV-accelerated H.264 encoding
+- basic APNG encoder and muxer
version 2.6:
diff --git a/doc/general.texi b/doc/general.texi
index 85ee219..589b423 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -222,6 +222,7 @@ library:
@tab Audio format used on the Nintendo Gamecube.
@item AFC @tab @tab X
@tab Audio format used on the Nintendo Gamecube.
+@item APNG @tab X @tab X
@item ASF @tab X @tab X
@item AST @tab X @tab X
@tab Audio format used on the Nintendo Wii.
@@ -508,6 +509,7 @@ following image formats are supported:
@item Alias PIX @tab X @tab X
@tab Alias/Wavefront PIX image format
@item animated GIF @tab X @tab X
+@item APNG @tab X @tab X
@item BMP @tab X @tab X
@tab Microsoft BMP image
@item BRender PIX @tab @tab X
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 2118ff2..5082101 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -80,6 +80,7 @@ OBJS-$(CONFIG_ANM_DEMUXER) += anm.o
OBJS-$(CONFIG_APC_DEMUXER) += apc.o
OBJS-$(CONFIG_APE_DEMUXER) += ape.o apetag.o img2.o
OBJS-$(CONFIG_APNG_DEMUXER) += apngdec.o
+OBJS-$(CONFIG_APNG_MUXER) += apngenc.o
OBJS-$(CONFIG_AQTITLE_DEMUXER) += aqtitledec.o subtitles.o
OBJS-$(CONFIG_ASF_DEMUXER) += asfdec.o asf.o asfcrypt.o \
avlanguage.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 26ccc27..ca45db8 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -74,7 +74,7 @@ void av_register_all(void)
REGISTER_DEMUXER (ANM, anm);
REGISTER_DEMUXER (APC, apc);
REGISTER_DEMUXER (APE, ape);
- REGISTER_DEMUXER (APNG, apng);
+ REGISTER_MUXDEMUX(APNG, apng);
REGISTER_DEMUXER (AQTITLE, aqtitle);
REGISTER_MUXDEMUX(ASF, asf);
REGISTER_MUXDEMUX(ASS, ass);
diff --git a/libavformat/apngenc.c b/libavformat/apngenc.c
new file mode 100644
index 0000000..7e3ea87
--- /dev/null
+++ b/libavformat/apngenc.c
@@ -0,0 +1,249 @@
+/*
+ * APNG muxer
+ * Copyright (c) 2015 Donny Yang
+ *
+ * first version by Donny Yang <w...@kota.moe>
+ *
+ * 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 <stdarg.h>
+#include <zlib.h>
+
+#include "avformat.h"
+#include "internal.h"
+#include "libavutil/avassert.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/log.h"
+#include "libavutil/opt.h"
+#include "libavcodec/png.h"
+#include "libavcodec/apng.h"
+
+static void apng_write_chunk(AVIOContext *io_context, uint32_t tag,
+ uint8_t* buf, size_t length)
+{
+ uint32_t crc;
+ uint8_t tagbuf[4];
+
+ avio_wb32(io_context, length);
+ crc = crc32(0, Z_NULL, 0);
+ AV_WB32(tagbuf, tag);
+ crc = crc32(crc, tagbuf, 4);
+ avio_wb32(io_context, tag);
+ if (length > 0) {
+ crc = crc32(crc, buf, length);
+ avio_write(io_context, buf, length);
+ }
+ avio_wb32(io_context, crc);
+}
+
+typedef struct APNGMuxContext {
+ AVClass *class;
+ uint32_t plays;
+ uint16_t last_delay_num;
+ uint16_t last_delay_den;
+
+ uint64_t acTL_offset;
+ uint32_t sequence_number;
+ uint32_t frame_number;
+
+ AVPacket *prev_packet;
+ uint16_t prev_delay_num;
+ uint16_t prev_delay_den;
+} APNGMuxContext;
+
+static int apng_write_header(AVFormatContext *format_context)
+{
+ AVStream *codec_stream;
+
+ if (format_context->nb_streams != 1 ||
+ format_context->streams[0]->codec->codec_type != AVMEDIA_TYPE_VIDEO ||
+ format_context->streams[0]->codec->codec_id != AV_CODEC_ID_APNG) {
+ av_log(format_context, AV_LOG_ERROR,
+ "APNG muxer supports only a single video APNG stream.\n");
+ return AVERROR(EINVAL);
+ }
+ codec_stream = format_context->streams[0];
+
+ if (codec_stream->time_base.num > USHRT_MAX || codec_stream->time_base.den
> USHRT_MAX) {
+ av_log(format_context, AV_LOG_WARNING,
+ "Frame rate is too high or specified too precisely. Unable to
copy losslessly.\n");
+ }
+
+ // Real headers are written when they are copied from the encoder
+
+ return 0;
+}
+
+static void flush_packet(AVFormatContext *format_context, AVPacket *packet)
+{
+ APNGMuxContext *apng = format_context->priv_data;
+ AVIOContext *io_context = format_context->pb;
+ AVStream *codec_stream = format_context->streams[0];
+ AVCodecContext *codec_context = codec_stream->codec;
+ uint8_t *frame_start;
+ uint8_t buf[26];
+ int64_t delay_num_raw, delay_den_raw;
+ int delay_num, delay_den;
+
+ av_assert0(apng->prev_packet);
+ frame_start = apng->prev_packet->data;
+
+ if (apng->frame_number == 0 && !packet) {
+ av_log(format_context, AV_LOG_WARNING, "Only a single frame so saving
as a normal PNG.\n");
+ } else {
+ if (apng->frame_number == 0) {
+ frame_start += 8; // skip PNGSIG
+ while (AV_RB32(frame_start + 4) != MKBETAG('I', 'D', 'A', 'T'))
+ frame_start += AV_RB32(frame_start) + 12;
+
+ // Write normal PNG headers
+ avio_write(io_context, apng->prev_packet->data, frame_start -
apng->prev_packet->data);
+
+ // Write animation control header
+ apng->acTL_offset = avio_tell(io_context);
+ AV_WB32(buf, UINT_MAX); // number of frames (filled in later)
+ AV_WB32(buf + 4, apng->plays);
+ apng_write_chunk(io_context, MKBETAG('a', 'c', 'T', 'L'), buf, 8);
+ }
+
+ if (packet) {
+ delay_num_raw = (packet->dts - apng->prev_packet->dts) *
codec_stream->time_base.num;
+ delay_den_raw = codec_stream->time_base.den;
+ av_reduce(&delay_num, &delay_den, delay_num_raw, delay_den_raw,
USHRT_MAX);
+ } else if (apng->last_delay_den > 0) {
+ delay_num = apng->last_delay_num;
+ delay_den = apng->last_delay_den;
+ } else {
+ delay_num = apng->prev_delay_num;
+ delay_den = apng->prev_delay_den;
+ }
+ apng->prev_delay_num = delay_num;
+ apng->prev_delay_den = delay_den;
+
+ AV_WB32(buf, apng->sequence_number);
+ AV_WB32(buf + 4, codec_context->width);
+ AV_WB32(buf + 8, codec_context->height);
+ AV_WB32(buf + 12, 0); // x offset
+ AV_WB32(buf + 16, 0); // y offset
+ AV_WB16(buf + 20, delay_num);
+ AV_WB16(buf + 22, delay_den);
+ buf[24] = APNG_DISPOSE_OP_BACKGROUND;
+ buf[25] = APNG_BLEND_OP_SOURCE;
+ apng_write_chunk(io_context, MKBETAG('f', 'c', 'T', 'L'), buf, 26);
+ ++apng->sequence_number;
+ }
+
+ if (apng->frame_number == 0) {
+ avio_write(io_context, frame_start, apng->prev_packet->data +
apng->prev_packet->size - frame_start);
+ } else {
+ // Need to replace IDAT chunks with fdAT chunks
+ do {
+ uint8_t *next_frame_start = frame_start + AV_RB32(frame_start) +
12;
+ size_t frame_size = AV_RB32(frame_start);
+
+ frame_start += 4;
+ frame_size += 4;
+
+ AV_WB32(frame_start, apng->sequence_number);
+ apng_write_chunk(io_context, MKBETAG('f', 'd', 'A', 'T'),
frame_start, frame_size);
+ ++apng->sequence_number;
+
+ frame_start = next_frame_start;
+ } while (frame_start < apng->prev_packet->data +
apng->prev_packet->size);
+ }
+ ++apng->frame_number;
+
+ av_free_packet(apng->prev_packet);
+ if (packet)
+ av_copy_packet(apng->prev_packet, packet);
+}
+
+static int apng_write_packet(AVFormatContext *format_context, AVPacket *packet)
+{
+ APNGMuxContext *apng = format_context->priv_data;
+
+ if (!apng->prev_packet) {
+ apng->prev_packet = av_malloc(sizeof(*apng->prev_packet));
+ if (!apng->prev_packet)
+ return AVERROR(ENOMEM);
+
+ av_copy_packet(apng->prev_packet, packet);
+ } else {
+ flush_packet(format_context, packet);
+ }
+
+ return 0;
+}
+
+static int apng_write_trailer(AVFormatContext *format_context)
+{
+ APNGMuxContext *apng = format_context->priv_data;
+ AVIOContext *io_context = format_context->pb;
+ uint8_t buf[8];
+
+ if (apng->prev_packet) {
+ flush_packet(format_context, NULL);
+ av_freep(&apng->prev_packet);
+ }
+
+ apng_write_chunk(io_context, MKBETAG('I', 'E', 'N', 'D'), NULL, 0);
+
+ if (apng->acTL_offset && io_context->seekable) {
+ avio_seek(io_context, apng->acTL_offset, SEEK_SET);
+
+ AV_WB32(buf, format_context->streams[0]->nb_frames);
+ AV_WB32(buf + 4, apng->plays);
+ apng_write_chunk(io_context, MKBETAG('a', 'c', 'T', 'L'), buf, 8);
+ }
+
+ return 0;
+}
+
+#define OFFSET(x) offsetof(APNGMuxContext, x)
+#define ENC AV_OPT_FLAG_ENCODING_PARAM
+static const AVOption options[] = {
+ { "plays", "Number of times to play the output: 0 - infinite loop, 1 - no
loop", OFFSET(plays),
+ AV_OPT_TYPE_INT, { .i64 = 1 }, 0, UINT_MAX, ENC },
+ { "final_delay_num", "Force delay numerator after the last frame",
OFFSET(last_delay_num),
+ AV_OPT_TYPE_INT, { .i64 = 0 }, 0, USHRT_MAX, ENC },
+ { "final_delay_den", "Force delay denominator after the last frame",
OFFSET(last_delay_den),
+ AV_OPT_TYPE_INT, { .i64 = 0 }, 0, USHRT_MAX, ENC },
+ { NULL },
+};
+
+static const AVClass apng_muxer_class = {
+ .class_name = "APNG muxer",
+ .item_name = av_default_item_name,
+ .version = LIBAVUTIL_VERSION_INT,
+ .option = options,
+};
+
+AVOutputFormat ff_apng_muxer = {
+ .name = "apng",
+ .long_name = NULL_IF_CONFIG_SMALL("Animated Portable Network
Graphics"),
+ .mime_type = "image/png",
+ .extensions = "png",
+ .priv_data_size = sizeof(APNGMuxContext),
+ .audio_codec = AV_CODEC_ID_NONE,
+ .video_codec = AV_CODEC_ID_APNG,
+ .write_header = apng_write_header,
+ .write_packet = apng_write_packet,
+ .write_trailer = apng_write_trailer,
+ .priv_class = &apng_muxer_class,
+ .flags = AVFMT_VARIABLE_FPS,
+};
diff --git a/libavformat/version.h b/libavformat/version.h
index a183d7f..82a57ee 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -30,8 +30,8 @@
#include "libavutil/version.h"
#define LIBAVFORMAT_VERSION_MAJOR 56
-#define LIBAVFORMAT_VERSION_MINOR 26
-#define LIBAVFORMAT_VERSION_MICRO 101
+#define LIBAVFORMAT_VERSION_MINOR 27
+#define LIBAVFORMAT_VERSION_MICRO 100
#define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
LIBAVFORMAT_VERSION_MINOR, \
--
2.3.4
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