On 2 April 2015 at 00:23, Michael Niedermayer <michae...@gmx.at> wrote:
> On Wed, Apr 01, 2015 at 01:17:50PM +0000, Donny Yang wrote:
> > On 1 April 2015 at 23:28, Michael Niedermayer <michae...@gmx.at> wrote:
> >
> > > On Wed, Apr 01, 2015 at 12:07:46PM +0000, Donny Yang wrote:
> > > > On 1 April 2015 at 22:57, Paul B Mahol <one...@gmail.com> wrote:
> > > >
> > > > > On 4/1/15, Donny Yang <w...@kota.moe> wrote:
> > > > > > On 1 April 2015 at 17:03, Paul B Mahol <one...@gmail.com> wrote:
> > > > > >
> > > > > >> Dana 31. 3. 2015. 22:59 osoba "Donny Yang" <w...@kota.moe>
> > > napisala je:
> > > > > >> > +#include <zlib.h>
> > > > > >>
> > > > > >> This is missing dependency on zlib in configure.
> > > > > >>
> > > > > > Fixed
> > > > > >
> > > > > >
> > > > >
> > > > > But this is more appropriate for APNG encoder. APNG muxer seems to
> not
> > > > > use zlib at all.
> > > > >
> > > > It's used for it's crc32 functions for editing/creating chunks.
> > >
> > > please use libavutil/crc*
> > >
> >
> > I applied the following patch to my code, but ffmpeg's functions seem to
> be
> > producing the wrong crc32 value.
> >
> > For example:
> > $ crc32 <(printf "acTL\x00\x00\x00\x14\x00\x00\x00\x00")
> > 1c2df152
> > While a `av_crc(av_crc_get_table(AV_CRC_32_IEEE), 0,
> > "acTL\x00\x00\x00\x14\x00\x00\x00\x00", 12)` returns 0xf6f7ccdd.
> > (using AV_CRC_32_IEEE_LE also produces an incorrect checksum)
> >
> > What am I doing wrong?
>
> http://www.w3.org/TR/PNG-CRCAppendix.html
> says:
>
> /* Update a running CRC with the bytes buf[0..len-1]--the CRC
> should be initialized to all 1's, and the transmitted value
> is the 1's complement of the final running CRC (see the
> crc() routine below)). */
>
Thanks. Patch has been updated.
From b9973cc5f5084df042c6c2f909a4a148b38af304 Mon Sep 17 00:00:00 2001
From: Donny Yang <w...@kota.moe>
Date: Sat, 28 Mar 2015 19:06:24 +1100
Subject: [PATCH 2/2] apng: Add a basic APNG muxer
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 | 271 +++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 276 insertions(+), 1 deletion(-)
create mode 100644 libavformat/apngenc.c
diff --git a/Changelog b/Changelog
index 75da156..ba0dff5 100644
--- a/Changelog
+++ b/Changelog
@@ -12,6 +12,7 @@ version <next>:
- Detelecine filter
- Intel QSV-accelerated H.264 encoding
- MMAL-accelerated H.264 decoding
+- 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..8dbe9e4
--- /dev/null
+++ b/libavformat/apngenc.c
@@ -0,0 +1,271 @@
+/*
+ * 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 "avformat.h"
+#include "internal.h"
+#include "libavutil/avassert.h"
+#include "libavutil/crc.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/log.h"
+#include "libavutil/opt.h"
+#include "libavcodec/png.h"
+#include "libavcodec/apng.h"
+
+typedef struct APNGMuxContext {
+ AVClass *class;
+
+ uint32_t plays;
+ AVRational last_delay;
+
+ uint64_t acTL_offset;
+ uint32_t frame_number;
+
+ AVPacket *prev_packet;
+ AVRational prev_delay;
+
+ int framerate_warned;
+} APNGMuxContext;
+
+static uint8_t *apng_find_chunk(uint32_t tag, uint8_t *buf, size_t length)
+{
+ size_t b;
+ for (b = 0; b < length; b += AV_RB32(buf + b) + 12)
+ if (AV_RB32(&buf[b + 4]) == tag)
+ return &buf[b];
+ return NULL;
+}
+
+static void apng_write_chunk(AVIOContext *io_context, uint32_t tag,
+ uint8_t *buf, size_t length)
+{
+ const AVCRC *crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
+ uint32_t crc = ~0U;
+ uint8_t tagbuf[4];
+
+ av_assert0(crc_table);
+
+ avio_wb32(io_context, length);
+ AV_WB32(tagbuf, tag);
+ crc = av_crc(crc_table, crc, tagbuf, 4);
+ avio_wb32(io_context, tag);
+ if (length > 0) {
+ crc = av_crc(crc_table, crc, buf, length);
+ avio_write(io_context, buf, length);
+ }
+ avio_wb32(io_context, ~crc);
+}
+
+static int apng_write_header(AVFormatContext *format_context)
+{
+ APNGMuxContext *apng = format_context->priv_data;
+
+ 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);
+ }
+
+ if (apng->last_delay.num > USHRT_MAX || apng->last_delay.den > USHRT_MAX) {
+ av_reduce(&apng->last_delay.num, &apng->last_delay.den,
+ apng->last_delay.num, apng->last_delay.den, USHRT_MAX);
+ av_log(format_context, AV_LOG_WARNING,
+ "Last frame delay is too precise. Reducing to %d/%d (%f).\n",
+ apng->last_delay.num, apng->last_delay.den, (double)apng->last_delay.num / apng->last_delay.den);
+ }
+
+ avio_wb64(format_context->pb, PNGSIG);
+ // Remaining 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;
+
+ av_assert0(apng->prev_packet);
+
+ if (apng->frame_number == 0 && !packet) {
+ uint8_t *existing_acTL_chunk;
+ uint8_t *existing_fcTL_chunk;
+
+ av_log(format_context, AV_LOG_WARNING, "Only a single frame so saving as a normal PNG.\n");
+
+ // Write normal PNG headers without acTL chunk
+ existing_acTL_chunk = apng_find_chunk(MKBETAG('a', 'c', 'T', 'L'), codec_context->extradata, codec_context->extradata_size);
+ if (existing_acTL_chunk) {
+ uint8_t *chunk_after_acTL = existing_acTL_chunk + AV_RB32(existing_acTL_chunk) + 12;
+ avio_write(io_context, codec_context->extradata, existing_acTL_chunk - codec_context->extradata);
+ avio_write(io_context, chunk_after_acTL, codec_context->extradata + codec_context->extradata_size - chunk_after_acTL);
+ } else {
+ avio_write(io_context, codec_context->extradata, codec_context->extradata_size);
+ }
+
+ // Write frame data without fcTL chunk
+ existing_fcTL_chunk = apng_find_chunk(MKBETAG('f', 'c', 'T', 'L'), apng->prev_packet->data, apng->prev_packet->size);
+ if (existing_fcTL_chunk) {
+ uint8_t *chunk_after_fcTL = existing_fcTL_chunk + AV_RB32(existing_fcTL_chunk) + 12;
+ avio_write(io_context, apng->prev_packet->data, existing_fcTL_chunk - apng->prev_packet->data);
+ avio_write(io_context, chunk_after_fcTL, apng->prev_packet->data + apng->prev_packet->size - chunk_after_fcTL);
+ } else {
+ avio_write(io_context, apng->prev_packet->data, apng->prev_packet->size);
+ }
+ } else {
+ uint8_t *existing_fcTL_chunk;
+
+ if (apng->frame_number == 0) {
+ uint8_t *existing_acTL_chunk;
+
+ // Write normal PNG headers
+ avio_write(io_context, codec_context->extradata, codec_context->extradata_size);
+
+ existing_acTL_chunk = apng_find_chunk(MKBETAG('a', 'c', 'T', 'L'), codec_context->extradata, codec_context->extradata_size);
+ if (!existing_acTL_chunk) {
+ uint8_t buf[8];
+ // 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);
+ }
+ }
+
+ existing_fcTL_chunk = apng_find_chunk(MKBETAG('f', 'c', 'T', 'L'), apng->prev_packet->data, apng->prev_packet->size);
+ if (existing_fcTL_chunk) {
+ AVRational delay;
+
+ existing_fcTL_chunk += 8;
+ delay.num = AV_RB16(existing_fcTL_chunk + 20);
+ delay.den = AV_RB16(existing_fcTL_chunk + 22);
+
+ if (delay.num == 0 && delay.den == 0) {
+ if (packet) {
+ int64_t delay_num_raw = (packet->dts - apng->prev_packet->dts) * codec_stream->time_base.num;
+ int64_t delay_den_raw = codec_stream->time_base.den;
+ if (!av_reduce(&delay.num, &delay.den, delay_num_raw, delay_den_raw, USHRT_MAX) &&
+ !apng->framerate_warned) {
+ av_log(format_context, AV_LOG_WARNING,
+ "Frame rate is too high or specified too precisely. Unable to copy losslessly.\n");
+ apng->framerate_warned = 1;
+ }
+ } else if (apng->last_delay.den > 0) {
+ delay = apng->last_delay;
+ } else {
+ delay = apng->prev_delay;
+ }
+
+ // Update frame control header with new delay
+ AV_WB16(existing_fcTL_chunk + 20, delay.num);
+ AV_WB16(existing_fcTL_chunk + 22, delay.den);
+ AV_WB32(existing_fcTL_chunk + 26, ~av_crc(av_crc_get_table(AV_CRC_32_IEEE_LE), ~0U, existing_fcTL_chunk - 4, 26 + 4));
+ }
+ apng->prev_delay = delay;
+ }
+
+ // Write frame data
+ avio_write(io_context, 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, apng->frame_number);
+ 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", "Force delay after the last frame", OFFSET(last_delay),
+ AV_OPT_TYPE_RATIONAL, { .dbl = 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,
+};
--
2.3.4
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