[FFmpeg-devel] [PATCH v2 03/18] avcodec/metaenc: added an encoder/decoder for timed metadata

[Carl Eugen Hoyos]

Hi!

2016-08-31 13:35 GMT+02:00 Erkki Seppälä <erkki.seppala.ext at nokia.com>:
> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> index 6ac6646..0d0447e6 100644
> --- a/libavcodec/avcodec.h
> +++ b/libavcodec/avcodec.h
> @@ -639,7 +639,7 @@ enum AVCodecID {
>      AV_CODEC_ID_DVD_NAV,
>      AV_CODEC_ID_TIMED_ID3,
>      AV_CODEC_ID_BIN_DATA,
> -
> +    AV_CODEC_ID_META,

Please do not remove the empty line.

> diff --git a/libavcodec/metacodec.c b/libavcodec/metacodec.c
> new file mode 100644
> index 0000000..bd8013c
> --- /dev/null
> +++ b/libavcodec/metacodec.c
> @@ -0,0 +1,95 @@
> +/*
> + * Copyright (c) 2015 Erkki Seppälä <erkki.seppala.ext at nokia.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 "libavutil/intreadwrite.h"
> +#include "internal.h"
> +#include "libavutil/opt.h"
> +#include "libavformat/avio.h"
> +
> +static int meta_encode(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame,
> +                       int *got_packet_ptr)
> +{
> +    *got_packet_ptr = 0;
> +
> +    av_packet_unref(avpkt);
> +    if (frame->buf) {
> +        avpkt->buf = av_buffer_ref(frame->buf[0]);
> +        if (!avpkt->buf)
> +          return AVERROR(ENOMEM);
> +        avpkt->data = frame->data[0];
> +    } else {
> +        avpkt->buf = av_buffer_alloc(frame->nb_samples);
> +        if (!avpkt->buf)
> +          return AVERROR(ENOMEM);
> +        avpkt->data = avpkt->buf;
> +        memcpy(avpkt->data, frame->data[0], frame->nb_samples);
> +    }
> +    avpkt->size = frame->nb_samples;
> +    avpkt->pts = frame->pts;
> +    avpkt->dts = frame->pts;
> +    *got_packet_ptr = 1;
> +
> +    return 0;
> +}
> +
> +static int meta_decode(AVCodecContext *avctx, void *data, int *got_packet_ptr, AVPacket *avpkt)
> +{
> +    AVFrame *metadata = data;
> +
> +    *got_packet_ptr = 0;
> +
> +    av_frame_unref(metadata);
> +    if (avpkt->buf) {
> +        metadata->buf[0] = av_buffer_ref(avpkt->buf);
> +        if (!metadata->buf[0])
> +            return AVERROR(ENOMEM);
> +        metadata->buf[0]->size = avpkt->size;
> +    } else {
> +        metadata->buf[0] = av_buffer_alloc(avpkt->size);
> +        if (!metadata->buf[0])
> +            return AVERROR(ENOMEM);
> +        metadata->data[0] = metadata->buf[0]->data;
> +        memcpy(metadata->data[0], avpkt->data, avpkt->size);
> +    }
> +
> +    metadata->nb_samples = avpkt->size;
> +    metadata->pts = avpkt->pts;
> +    metadata->pkt_pts = avpkt->pts;
> +    metadata->pkt_dts = avpkt->dts;
> +    *got_packet_ptr = 1;
> +
> +    return 0;
> +}
> +
> +AVCodec ff_meta_encoder = {
> +    .name           = "meta",
> +    .long_name      = NULL_IF_CONFIG_SMALL("Metadata Encoder"),
> +    .type           = AVMEDIA_TYPE_DATA,
> +    .id             = AV_CODEC_ID_META,
> +    .encode2        = meta_encode,
> +};
> +
> +AVCodec ff_meta_decoder = {
> +    .name           = "meta",
> +    .long_name      = NULL_IF_CONFIG_SMALL("Metadata Decoder"),
> +    .type           = AVMEDIA_TYPE_DATA,
> +    .id             = AV_CODEC_ID_META,
> +    .decode         = meta_decode,
> +};

You either have to add some "#if"'s around the code - configure allows to
enable / disable the encoders and decoders separately - or split the file.
Since the encoder and decoder do not share code, this seems simpler,

Carl Eugen