[FFmpeg-devel] [PATCH] parser: error out if the codec doesn't match

[Hendrik Leppkes]

On Tue, Jan 5, 2016 at 11:46 AM, Michael Niedermayer
<michael at niedermayer.cc> wrote:
> On Tue, Jan 05, 2016 at 12:44:40AM +0100, Andreas Cadhalpun wrote:
>> Otherwise this can have some surprising effects (crashes), so let's
>> better not allow it.
>>
>> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
>> ---
>>  libavcodec/parser.c | 11 +++++++++++
>>  1 file changed, 11 insertions(+)
>>
>> diff --git a/libavcodec/parser.c b/libavcodec/parser.c
>> index 2809158..1f38edb 100644
>> --- a/libavcodec/parser.c
>> +++ b/libavcodec/parser.c
>> @@ -141,6 +141,17 @@ int av_parser_parse2(AVCodecParserContext *s, AVCodecContext *avctx,
>>      int index, i;
>>      uint8_t dummy_buf[AV_INPUT_BUFFER_PADDING_SIZE];
>>
>> +    if (avctx->codec_id != s->parser->codec_ids[0] &&
>> +        avctx->codec_id != s->parser->codec_ids[1] &&
>> +        avctx->codec_id != s->parser->codec_ids[2] &&
>> +        avctx->codec_id != s->parser->codec_ids[3] &&
>> +        avctx->codec_id != s->parser->codec_ids[4]) {
>> +        av_log(avctx, AV_LOG_ERROR,
>> +               "The parser doesn't match the codec %s.\n",
>> +               avcodec_get_name(avctx->codec_id));
>> +        return buf_size;
>> +    }
>
> does it also work to check if a parser is set when the codec id
> is changed ? as in below
>
> (that would avoid doing 5 extra checks per packet)
>
> --- a/libavformat/utils.c
> +++ b/libavformat/utils.c
> @@ -521,6 +521,9 @@ fail:
>
>  static void force_codec_ids(AVFormatContext *s, AVStream *st)
>  {
> +    if (st->parser)
> +        return;
> +
>      switch (st->codec->codec_type) {
>      case AVMEDIA_TYPE_VIDEO:
>          if (s->video_codec_id)
>
>

Maybe it should just delete the existing parser if the codec id is
changed here instead of refusing the change?

- Hendrik