[FFmpeg-devel] [PATCH v1] avcodec/h264_parse: retry decoding SPS with complete NAL

[James Almer]

On 8/18/2019 10:41 PM, Jun Li wrote:
> Fix #6591
> The content has no rbsp_stop_one_bit for ending the SPS, that
> causes the decoding SPS failure, results decoding frame failure as well.
> The patch is just adding a retry with complete NALU.
> ---
>  libavcodec/h264_parse.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/h264_parse.c b/libavcodec/h264_parse.c
> index ac31f54e07..a2267a0610 100644
> --- a/libavcodec/h264_parse.c
> +++ b/libavcodec/h264_parse.c
> @@ -376,8 +376,14 @@ static int decode_extradata_ps(const uint8_t *data, int size, H264ParamSets *ps,
>          switch (nal->type) {
>          case H264_NAL_SPS:
>              ret = ff_h264_decode_seq_parameter_set(&nal->gb, logctx, ps, 0);
> -            if (ret < 0)
> -                goto fail;
> +            if (ret < 0) {
> +                GetBitContext tmp_gb = nal->gb;
> +                av_log(logctx, AV_LOG_DEBUG,
> +                   "SPS decoding failure (maybe missing rbsp_stop_one_bit), trying again with the complete NAL\n");
> +                init_get_bits8(&tmp_gb, nal->raw_data + 1, nal->raw_size - 1);
> +                if ((ret = ff_h264_decode_seq_parameter_set(&tmp_gb, logctx, ps, 0)) < 0)
> +                    goto fail;
> +            }
>              break;
>          case H264_NAL_PPS:
>              ret = ff_h264_decode_picture_parameter_set(&nal->gb, logctx, ps,

Copy instead the code from decode_nal_units() in h264dec.c, which checks
first with the complete NAL, and then calls
ff_h264_decode_seq_parameter_set() with the ignore_truncation parameter
set to 1 as a last resort.