[FFmpeg-devel] [PATCH] Write WebVTT output files
Paul B Mahol
onemda at gmail.com
Wed Jun 12 21:04:03 CEST 2013
On 6/12/13, Paul B Mahol <onemda at gmail.com> wrote:
> On 6/12/13, Matthew Heaney <matthewjheaney at google.com> wrote:
>> This revision creates a WebVTT muxer, that outputs files having the
>> format described in the following specification:
>>
>> http://dev.w3.org/html5/webvtt/
>> ---
>
> $subject is wrong, it should be something like: "webvtt muxer"
>
>> doc/general.texi | 2 +-
>> libavformat/Makefile | 1 +
>> libavformat/allformats.c | 2 +-
>> libavformat/version.h | 2 +-
>> libavformat/webvttenc.c | 116
>> +++++++++++++++++++++++++++++++++++++++++++++++
>> 5 files changed, 120 insertions(+), 3 deletions(-)
>> create mode 100644 libavformat/webvttenc.c
>>
>> diff --git a/doc/general.texi b/doc/general.texi
>> index a83b55e..0cddf9f 100644
>> --- a/doc/general.texi
>> +++ b/doc/general.texi
>> @@ -957,7 +957,7 @@ performance on systems without hardware floating
>> point
>> support).
>> @item TED Talks captions @tab @tab X @tab @tab X
>> @item VobSub (IDX+SUB) @tab @tab X @tab @tab X
>> @item VPlayer @tab @tab X @tab @tab X
>> - at item WebVTT @tab @tab X @tab @tab X
>> + at item WebVTT @tab X @tab X @tab @tab X
>
> Hmm, you flag encoder too, but this patch adds muxer only.
Ignore, i'm blind.
>
>> @item XSUB @tab @tab @tab X @tab X
>> @end multitable
>>
>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>> index 5438b48..3cb076b 100644
>> --- a/libavformat/Makefile
>> +++ b/libavformat/Makefile
>> @@ -393,6 +393,7 @@ OBJS-$(CONFIG_WEBM_MUXER) +=
>> matroskaenc.o matroska.o \
>> isom.o avc.o \
>> flacenc_header.o
>> avlanguage.o
>> wv.o
>> OBJS-$(CONFIG_WEBVTT_DEMUXER) += webvttdec.o subtitles.o
>> +OBJS-$(CONFIG_WEBVTT_MUXER) += webvttenc.o subtitles.o
>> OBJS-$(CONFIG_WSAUD_DEMUXER) += westwood_aud.o
>> OBJS-$(CONFIG_WSVQA_DEMUXER) += westwood_vqa.o
>> OBJS-$(CONFIG_WTV_DEMUXER) += wtvdec.o wtv.o asfdec.o
>> asf.o
>> asfcrypt.o \
>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>> index 6274a75..d4a2d27 100644
>> --- a/libavformat/allformats.c
>> +++ b/libavformat/allformats.c
>> @@ -292,7 +292,7 @@ void av_register_all(void)
>> REGISTER_MUXDEMUX(WAV, wav);
>> REGISTER_DEMUXER (WC3, wc3);
>> REGISTER_MUXER (WEBM, webm);
>> - REGISTER_DEMUXER (WEBVTT, webvtt);
>> + REGISTER_MUXDEMUX(WEBVTT, webvtt);
>> REGISTER_DEMUXER (WSAUD, wsaud);
>> REGISTER_DEMUXER (WSVQA, wsvqa);
>> REGISTER_MUXDEMUX(WTV, wtv);
>> diff --git a/libavformat/version.h b/libavformat/version.h
>> index 8db210e..69e9e2c 100644
>> --- a/libavformat/version.h
>> +++ b/libavformat/version.h
>> @@ -30,7 +30,7 @@
>> #include "libavutil/avutil.h"
>>
>> #define LIBAVFORMAT_VERSION_MAJOR 55
>> -#define LIBAVFORMAT_VERSION_MINOR 8
>> +#define LIBAVFORMAT_VERSION_MINOR 9
>> #define LIBAVFORMAT_VERSION_MICRO 102
>
> This needs to be set back to 100, when changing minor/major.
>
>>
>> #define LIBAVFORMAT_VERSION_INT
>> AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR,
>> \
>> diff --git a/libavformat/webvttenc.c b/libavformat/webvttenc.c
>> new file mode 100644
>> index 0000000..f0f91a5
>> --- /dev/null
>> +++ b/libavformat/webvttenc.c
>> @@ -0,0 +1,116 @@
>> +/*
>> + * Copyright (c) 2013 Matthew Heaney
>> + *
>> + * 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
>> + * WebVTT subtitle muxer
>> + * @see http://dev.w3.org/html5/webvtt/
>> + */
>> +
>> +#include "avformat.h"
>> +#include "internal.h"
>> +
>> +static void webvtt_write_time(AVIOContext *pb, int64_t millisec)
>> +{
>> + int64_t sec, min, hour;
>> + sec = millisec / 1000;
>> + millisec -= 1000 * sec;
>> + min = sec / 60;
>> + sec -= 60 * min;
>> + hour = min / 60;
>> + min -= 60 * hour;
>> +
>> + if (hour > 0)
>> + avio_printf(pb, "%ld:", hour);
>> +
>> + avio_printf(pb, "%02ld:%02ld.%03ld", min, sec, millisec);
>> +}
>> +
>> +static int webvtt_write_header(AVFormatContext *ctx)
>> +{
>> + AVStream *s = ctx->streams[0];
>> + AVIOContext *pb = ctx->pb;
>> +
>> + avpriv_set_pts_info(s, 64, 1, 1000);
>> +
>> + avio_printf(pb, "WEBVTT\n");
>> + avio_flush(pb);
>> +
>> + return 0;
>> +}
>> +
>> +static int webvtt_write_packet(AVFormatContext *ctx, AVPacket *pkt)
>> +{
>> + AVIOContext *pb = ctx->pb;
>> + int id_size, settings_size;
>> + uint8_t *id, *settings;
>> +
>> + // Write cue separator.
>> +
>> + avio_printf(pb, "\n");
>> +
>> + // Write cue id (but only if present).
>> +
>> + id = av_packet_get_side_data(pkt, AV_PKT_DATA_WEBVTT_IDENTIFIER,
>> + &id_size);
>> +
>> + if (id != NULL && id_size > 0) {
>> + avio_write(pb, id, id_size);
>> + avio_printf(pb, "\n");
>> + }
>> +
>> + // Write timestamp and (optional) settings.
>> +
>> + webvtt_write_time(pb, pkt->pts);
>> +
>> + avio_printf(pb, " ---> ");
>> +
>> + webvtt_write_time(pb, pkt->pts + pkt->duration);
>> +
>> + settings_size = 0;
>> + settings = av_packet_get_side_data(pkt, AV_PKT_DATA_WEBVTT_SETTINGS,
>> + &settings_size);
>> +
>> + if (settings != NULL && settings_size > 0) {
>> + avio_printf(pb, " ");
>> + avio_write(pb, settings, settings_size);
>> + }
>> +
>> + avio_printf(pb, "\n");
>> +
>> + // Write cue text.
>> +
>> + avio_write(pb, pkt->data, pkt->size);
>> + avio_printf(pb, "\n");
>> +
>> + avio_flush(pb);
>
> Should not be needed.
>
>> +
>> + return 0;
>> +}
>> +
>> +AVOutputFormat ff_webvtt_muxer = {
>> + .name = "webvtt",
>> + .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
>> + .extensions = "vtt",
>> + .mime_type = "text/vtt",
>> + .subtitle_codec = AV_CODEC_ID_WEBVTT,
>> + .write_header = webvtt_write_header,
>> + .write_packet = webvtt_write_packet,
>> +};
>> --
>> 1.8.3
>>
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>>
>
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