[FFmpeg-devel] [PATCH 2/2] avformat: add kvag muxer

[James Almer]

On 4/10/2020 12:10 AM, Zane van Iperen wrote:
> Signed-off-by: Zane van Iperen <zane at zanevaniperen.com>
> ---
>  Changelog                |  1 +
>  libavformat/Makefile     |  1 +
>  libavformat/allformats.c |  1 +
>  libavformat/kvag.c       | 78 +++++++++++++++++++++++++++++++++++++++-
>  libavformat/version.h    |  2 +-
>  5 files changed, 81 insertions(+), 2 deletions(-)
> 
> diff --git a/Changelog b/Changelog
> index b4fff44329..b2de88484b 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -57,6 +57,7 @@ version <next>:
>  - overlay_cuda filter
>  - switch from AvxSynth to AviSynth+ on Linux
>  - Simon & Schuster Interactive ADPCM encoder
> +- Real War KVAG muxer
>  
>  
>  version 4.2:
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index 8fd0d43721..ff920c4373 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -285,6 +285,7 @@ OBJS-$(CONFIG_JACOSUB_MUXER)             += jacosubenc.o rawenc.o
>  OBJS-$(CONFIG_JV_DEMUXER)                += jvdec.o
>  OBJS-$(CONFIG_KUX_DEMUXER)               += flvdec.o
>  OBJS-$(CONFIG_KVAG_DEMUXER)              += kvag.o
> +OBJS-$(CONFIG_KVAG_MUXER)                += kvag.o
>  OBJS-$(CONFIG_LATM_MUXER)                += latmenc.o rawenc.o
>  OBJS-$(CONFIG_LMLM4_DEMUXER)             += lmlm4.o
>  OBJS-$(CONFIG_LOAS_DEMUXER)              += loasdec.o rawdec.o
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index 39d2c352f5..e12b50375c 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -220,6 +220,7 @@ extern AVOutputFormat ff_jacosub_muxer;
>  extern AVInputFormat  ff_jv_demuxer;
>  extern AVInputFormat  ff_kux_demuxer;
>  extern AVInputFormat  ff_kvag_demuxer;
> +extern AVOutputFormat ff_kvag_muxer;
>  extern AVOutputFormat ff_latm_muxer;
>  extern AVInputFormat  ff_lmlm4_demuxer;
>  extern AVInputFormat  ff_loas_demuxer;
> diff --git a/libavformat/kvag.c b/libavformat/kvag.c
> index 71b0eb4118..d337d1cd4f 100644
> --- a/libavformat/kvag.c
> +++ b/libavformat/kvag.c
> @@ -1,5 +1,5 @@
>  /*
> - * Simon & Schuster Interactive VAG demuxer
> + * Simon & Schuster Interactive VAG (de)muxer
>   *
>   * Copyright (C) 2020 Zane van Iperen (zane at zanevaniperen.com)
>   *
> @@ -34,6 +34,7 @@ typedef struct KVAGHeader {
>      uint16_t    stereo;
>  } KVAGHeader;
>  
> +#if CONFIG_KVAG_DEMUXER
>  static int kvag_probe(const AVProbeData *p)
>  {
>      if (AV_RL32(p->buf) != KVAG_TAG)
> @@ -115,3 +116,78 @@ AVInputFormat ff_kvag_demuxer = {
>      .read_header    = kvag_read_header,
>      .read_packet    = kvag_read_packet
>  };
> +#endif
> +
> +#if CONFIG_KVAG_MUXER
> +static int kvag_write_header(AVFormatContext *s)
> +{
> +    AVCodecParameters *par;
> +    uint8_t buf[KVAG_HEADER_SIZE];
> +
> +    if (s->nb_streams != 1) {
> +        av_log(s, AV_LOG_ERROR, "KVAG files have exactly one stream\n");
> +        return AVERROR(EINVAL);
> +    }
> +
> +    par = s->streams[0]->codecpar;
> +
> +    if (par->codec_id != AV_CODEC_ID_ADPCM_IMA_SSI) {
> +        AVCodec *codec = avcodec_find_encoder(par->codec_id);

avcodec_get_name(par->codec_id);

> +        av_log(s, AV_LOG_ERROR, "%s codec not supported\n",
> +               codec ? codec->name : "NONE");

With the above change codec will never be NULL, so you can remove this
check.

> +        return AVERROR(EINVAL);
> +    }
> +
> +    if (par->channels > 2) {
> +        av_log(s, AV_LOG_ERROR, "KVAG files only support up to 2 channels\n");
> +        return AVERROR(EINVAL);
> +    }

Everything up to this check should be in a separate
AVOutputFormat.init() function instead.

> +
> +    AV_WL32(buf +  0, KVAG_TAG);
> +    AV_WL32(buf +  4, 0); /* Data size, we fix this up later. */
> +    AV_WL32(buf +  8, par->sample_rate);
> +    AV_WL16(buf + 12, par->channels == 2);
> +
> +    avio_write(s->pb, buf, sizeof(buf));
> +    return 0;
> +}
> +
> +static int kvag_write_packet(AVFormatContext *s, AVPacket *pkt)
> +{
> +    avio_write(s->pb, pkt->data, pkt->size);
> +    return 0;
> +}

Use ff_raw_write_packet() instead.

> +
> +static int kvag_write_trailer(AVFormatContext *s)
> +{
> +    int64_t file_size, data_size;
> +
> +    if (!(s->pb->seekable & AVIO_SEEKABLE_NORMAL))
> +        return 0;
> +
> +    file_size = avio_tell(s->pb);
> +    data_size = file_size - KVAG_HEADER_SIZE;
> +    if (data_size < UINT32_MAX) {
> +        avio_seek(s->pb, 4, SEEK_SET);
> +        avio_wl32(s->pb, (uint32_t)data_size);
> +        avio_seek(s->pb, file_size, SEEK_SET);
> +    } else {
> +        av_log(s, AV_LOG_ERROR,
> +               "Filesize %"PRId64" invalid for KVAG, output file will be broken\n",
> +               file_size);

This should be a warning.

And you should also print a warning in the non seekable case, if not
writing the data_size value will result in an invalid file.

> +    }
> +
> +    return 0;
> +}
> +
> +AVOutputFormat ff_kvag_muxer = {
> +    .name           = "kvag",
> +    .long_name      = NULL_IF_CONFIG_SMALL("Simon & Schuster Interactive VAG"),
> +    .extensions     = "vag",
> +    .audio_codec    = AV_CODEC_ID_ADPCM_IMA_SSI,
> +    .video_codec    = AV_CODEC_ID_NONE,
> +    .write_header   = kvag_write_header,
> +    .write_packet   = kvag_write_packet,
> +    .write_trailer  = kvag_write_trailer
> +};
> +#endif
> diff --git a/libavformat/version.h b/libavformat/version.h
> index 18c2f5fec2..493a0b337f 100644
> --- a/libavformat/version.h
> +++ b/libavformat/version.h
> @@ -32,7 +32,7 @@
>  // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
>  // Also please add any ticket numbers that you believe might be affected here
>  #define LIBAVFORMAT_VERSION_MAJOR  58
> -#define LIBAVFORMAT_VERSION_MINOR  42
> +#define LIBAVFORMAT_VERSION_MINOR  43
>  #define LIBAVFORMAT_VERSION_MICRO 100
>  
>  #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
>