Dana 31. 3. 2015. 22:59 osoba "Donny Yang" <w...@kota.moe> napisala je:
>
> 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 | 269
+++++++++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 274 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..0e9af89
> --- /dev/null
> +++ b/libavformat/apngenc.c
> @@ -0,0 +1,269 @@
> +/*
> + * 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 <zlib.h>
This is missing dependency on zlib in configure.
> +
> +#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"
> +
> +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)
> +{
> + 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);
> +}
> +
> +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, crc32(crc32(0, Z_NULL,
0), 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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> ffmpeg-devel@ffmpeg.org
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