[FFmpeg-devel] [PATCH] libavcodec: Do not return encoding errors when -sub_charenc_mode is do_nothing

Paul B Mahol onemda at gmail.com
Thu Aug 29 12:49:29 CEST 2013

On 8/29/13, Eelco Lempsink <eelco at lempsink.nl> wrote:
> Hi Nicolas,
> On 28 aug. 2013, at 23:41, Nicolas George <nicolas.george at normalesup.org>
> wrote:
>> Le primidi 11 fructidor, an CCXXI, Eelco Lempsink a ecrit :
>>> Signed-off-by: Eelco Lempsink <eml at tupil.com>
>>> ---
>>> libavcodec/utils.c | 15 ++++++++++-----
>>> 1 file changed, 10 insertions(+), 5 deletions(-)
>> This is not what << do nothing >> is meant for. It is meant for situations
>> where the muxer already did the job, and the check to ensure that the job
>> was done properly is still relevant.
>> If you want to bypass the check, please add a dedicated option, and
>> clearly
>> document that any application that uses it is misdesigned and will not
>> work
>> once the full recoding API is implemented.
> First off, I'm really happy to see FFmpeg taking character encodings into
> consideration.  I honestly thought that `do_nothing' meant something else, I
> didn't mean to send a snark-patch.  (I only saw the previous discussion
> after I send the patch.)
> That said, the current implementation is incomplete and does not belong in a
> release version, in my opinion.  When using FFmpeg in part of a larger
> workflow where character encodings are not known in advance, you simply need
> all the bits to properly guess the encoding.  Even when the recoding API is
> fully implemented there will be cases where FFmpeg will make the wrong guess
> (the alternative would be to wait until all the data is known and then make
> the guess, which would be a problem for streams).
> I have some experience doing character encoding detection using libicu
> (http://site.icu-project.org) since that is what we currently use to process
> the output of FFmpeg, and I'd be happy to offer advice and help, if wanted.
> How about this:
> - Rename the `do_nothing' option to `assume_utf8'.
> - Add a `passthrough' option.
> Would that be an acceptable patch?

To me? Sure. For Nicolas, probably not.

> Regards,
> Eelco Lempsink

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