[FFmpeg-devel] [PATCH]lavf/pcmdec: Map mime_type audio/L16 to the s16le demuxer

[Nicolas George]

Le nonidi 19 thermidor, an CCXXIV, Carl Eugen Hoyos a écrit :
> Hi!
> 
> Attached patch implements RFC 2586.
> 
> Please comment, Carl Eugen

> From ba470c643c836826d75854e3e3539eb09ddd288a Mon Sep 17 00:00:00 2001
> From: Carl Eugen Hoyos <cehoyos at ag.or.at>
> Date: Fri, 5 Aug 2016 12:22:17 +0200
> Subject: [PATCH] lavf/pcmdec: Map mime_type audio/L16 to s16le as specified
>  in RFC 2586.
> 
> ---
>  libavformat/pcmdec.c |   63 +++++++++++++++++++++++++++++++++-----------------
>  1 file changed, 42 insertions(+), 21 deletions(-)
> 
> diff --git a/libavformat/pcmdec.c b/libavformat/pcmdec.c
> index df94345..36ef2c2 100644
> --- a/libavformat/pcmdec.c
> +++ b/libavformat/pcmdec.c
> @@ -36,6 +36,7 @@ static int pcm_read_header(AVFormatContext *s)
>  {
>      PCMAudioDemuxerContext *s1 = s->priv_data;
>      AVStream *st;
> +    uint8_t *mime_type_opt = NULL;
>  
>      st = avformat_new_stream(s, NULL);
>      if (!st)
> @@ -47,6 +48,25 @@ static int pcm_read_header(AVFormatContext *s)
>      st->codecpar->sample_rate = s1->sample_rate;
>      st->codecpar->channels    = s1->channels;
>  
> +    av_opt_get(s->pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
> +    if (mime_type_opt) {

> +        const char *mime_type = mime_type_opt;

I do not understand the need for that line.

> +        size_t len = strlen(s->iformat->mime_type);

Maybe I am missing something obvious, but I think s->iformat->mime_type is
NULL for all the other formats. It needs to be checked.

> +        int rate, channels = 0;
> +        if (!av_strncasecmp(s->iformat->mime_type, mime_type, len)) {

> +            if (   !sscanf(mime_type + len, ";rate=%d;channels=%d", &rate, &channels)

If I understand the way MIME type works, ";channels=2;rate=48000" would be
exactly as valid, and spaces can surround the semicolons.

> +                || !rate) {
> +                av_log(s, AV_LOG_ERROR,
> +                       "Invalid sample_rate found in mime_type \"%s\"\n",
> +                       mime_type);
> +                return AVERROR_INVALIDDATA;
> +            }
> +            st->codecpar->sample_rate = rate;
> +            if (channels)
> +                st->codecpar->channels = channels;
> +        }
> +    }
> +
>      st->codecpar->bits_per_coded_sample =
>          av_get_bits_per_sample(st->codecpar->codec_id);
>  
> @@ -65,7 +85,7 @@ static const AVOption pcm_options[] = {
>      { NULL },
>  };
>  
> -#define PCMDEF(name_, long_name_, ext, codec)               \

> +#define PCMDEF(name_, long_name_, ext, codec, mime_type_)   \

Instead of changing PCMDEF and all the subsequent declarations, you can
create a new macro PCMDEF_WITH_MIME.

Even simpler: make PCMDEF varadic, add __ARGS__ in the structure definition.
Then, adding the MIME type is just a matter of adding ".mime_type = ..." in
the macro call.

Regards,

-- 
  Nicolas George
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