[FFmpeg-devel] [PATCH] avcodec: parse options from AVCodec.bsfs

[James Almer]

On 7/18/2018 3:57 PM, Aman Gupta wrote:
> From: Aman Gupta <aman at tmm1.net>
> 

avcodec/decode: parse options from AVCodec.bsfs

> Fixes a bug that would prevent using multiple comma-separated filters,
> and allows options to be passed to each filter.
> 
> Based on similar loop in ffmpeg_opt.c's new_output_stream().
> 
> Signed-off-by: Aman Gupta <aman at tmm1.net>
> ---
>  libavcodec/decode.c | 47 ++++++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 40 insertions(+), 7 deletions(-)
> 
> diff --git a/libavcodec/decode.c b/libavcodec/decode.c
> index 6a3a4df179..67b7443b9d 100644
> --- a/libavcodec/decode.c
> +++ b/libavcodec/decode.c
> @@ -36,6 +36,7 @@
>  #include "libavutil/imgutils.h"
>  #include "libavutil/internal.h"
>  #include "libavutil/intmath.h"
> +#include "libavutil/opt.h"
>  
>  #include "avcodec.h"
>  #include "bytestream.h"
> @@ -195,27 +196,33 @@ static int bsfs_init(AVCodecContext *avctx)
>      while (bsfs_str && *bsfs_str) {
>          AVBSFContext **tmp;
>          const AVBitStreamFilter *filter;
> -        char *bsf;
> +        char *bsf, *bsf_options_str, *bsf_name;
>  
>          bsf = av_get_token(&bsfs_str, ",");
>          if (!bsf) {
>              ret = AVERROR(ENOMEM);
>              goto fail;
>          }
> +        bsf_name = av_strtok(bsf, "=", &bsf_options_str);
> +        if (!bsf_name) {
> +            av_freep(&bsf);
> +            ret = AVERROR(ENOMEM);
> +            goto fail;
> +        }
>  
> -        filter = av_bsf_get_by_name(bsf);
> +        filter = av_bsf_get_by_name(bsf_name);
>          if (!filter) {
>              av_log(avctx, AV_LOG_ERROR, "A non-existing bitstream filter %s "
>                     "requested by a decoder. This is a bug, please report it.\n",
> -                   bsf);
> -            ret = AVERROR_BUG;
> +                   bsf_name);
>              av_freep(&bsf);
> +            ret = AVERROR_BUG;
>              goto fail;
>          }
> -        av_freep(&bsf);
>  
>          tmp = av_realloc_array(s->bsfs, s->nb_bsfs + 1, sizeof(*s->bsfs));
>          if (!tmp) {
> +            av_freep(&bsf);
>              ret = AVERROR(ENOMEM);
>              goto fail;
>          }
> @@ -223,8 +230,10 @@ static int bsfs_init(AVCodecContext *avctx)
>          s->nb_bsfs++;
>  
>          ret = av_bsf_alloc(filter, &s->bsfs[s->nb_bsfs - 1]);
> -        if (ret < 0)
> +        if (ret < 0) {
> +            av_freep(&bsf);
>              goto fail;
> +        }
>  
>          if (s->nb_bsfs == 1) {
>              /* We do not currently have an API for passing the input timebase into decoders,
> @@ -238,12 +247,36 @@ static int bsfs_init(AVCodecContext *avctx)
>              ret = avcodec_parameters_copy(s->bsfs[s->nb_bsfs - 1]->par_in,
>                                            s->bsfs[s->nb_bsfs - 2]->par_out);
>          }
> -        if (ret < 0)
> +        if (ret < 0) {
> +            av_freep(&bsf);
>              goto fail;
> +        }
> +
> +        if (bsf_options_str && filter->priv_class) {
> +            const AVOption *opt = av_opt_next(s->bsfs[s->nb_bsfs - 1]->priv_data, NULL);
> +            const char * shorthand[2] = {NULL};
> +
> +            if (opt)
> +                shorthand[0] = opt->name;
> +
> +            ret = av_opt_set_from_string(s->bsfs[s->nb_bsfs - 1]->priv_data, bsf_options_str, shorthand, "=", ":");
> +            if (ret < 0) {
> +                av_log(avctx, AV_LOG_ERROR, "Invalid options for bitstream filter %s "
> +                       "requested by the decoder. This is a bug, please report it.\n",
> +                       bsf_name);
> +                av_freep(&bsf);
> +                ret = AVERROR_BUG;
> +                goto fail;
> +            }

As i said on IRC, av_opt_set_from_string() can return ENOMEM which is
not a bug in the string contents, so do something like

if (ret < 0) {
  if (ret != AVERROR(ENOMEM)) {
    av_log(avctx, AV_LOG_ERROR, "Invalid options for bitstream filter %s "
           "requested by the decoder. This is a bug, please report it.\n",
           bsf_name);
    ret = AVERROR_BUG;
  }
  av_freep(&bsf);
  goto fail;
}

> +        }
> +        av_freep(&bsf);
>  
>          ret = av_bsf_init(s->bsfs[s->nb_bsfs - 1]);
>          if (ret < 0)
>              goto fail;
> +
> +        if (*bsfs_str)
> +            bsfs_str++;
>      }
>  
>      return 0;
> 

Should be ok otherwise.