Bug#803825: hedgewars: FTBFS with FFmpeg 2.9

[Andreas Cadhalpun]

Hi Gianfranco,

On 04.11.2015 10:49, Gianfranco Costamagna wrote:
>> That's not correct: the alternatives have been present for a
>> long time, so that the deprecated functions will be removed
>> in the next version.
> 
> thanks, this is something I was wondering, even if I couldn't easily find
> when they were introduced.

This is documented in FFmpeg's APIchanges [1], also installed in ffmpeg-doc.

>> While this will probably work, it's not entirely correct.
>> You can use:
>> * for AVPixelFormat, AV_PIX_FMT_*:
>> #if LIBAVUTIL_VERSION_MAJOR > 51
>> * for av_frame_alloc/av_frame_free:
>> #if LIBAVUTIL_VERSION_MAJOR > 52
>> * for av_stream_get_end_pts:
>> #if LIBAVFORMAT_VERSION_MAJOR > 55
> 
> thanks, I committed this on the upstream pull request, giving you the commit authorship.

Unfortunately, you didn't copy this correctly...

On 04.11.2015 11:01, Gianfranco Costamagna wrote:
> unfortunately this change breaks libav 4:0.8.17-0ubuntu0.12.04.1 

...so it doesn't work.

You always used LIBAVCODEC_VERSION_MAJOR, while that should have been
LIBAVUTIL_VERSION_MAJOR or LIBAVFORMAT_VERSION_MAJOR.

If done correctly, it will surely work fine with Libav 0.8, which has
only libavutil 51 and libavformat 53.

> While I like the solution, I'm really worried about backporting hedgewars,
> (and this is why I took 55 as separator), because that way I wasn't changing the "current" behaviour.
> 
> Now the next backports will take some new functionalities, while before they were using a deprecated code...
> 
> This sounds scary to me, but if upstream applies the patch I have one year until the next backport need
> (I'm backporting hedgewars without the above fixes for this new release)
> 
> let me know if you can reassure me because the changes are "safe" or whatever :)

Yes, these changes are safe:
 * AVPixelFormat, AV_PIX_FMT_*:
Only the names changed (due to being too generic before). The binary will be identical.
 * av_frame_alloc/av_frame_free:
These functions are now in libavutil, while avcodec_alloc_frame/avcodec_free_frame
were in libavcodec. Actually hedgewars used av_free to free the frames, which
can leak memory, so using the correct free function is definitely an improvement.
 * for av_stream_get_end_pts:
This is just a getter function for pts.val, which is made private, no functional change.

Best regards,
Andreas


1: https://anonscm.debian.org/cgit/pkg-multimedia/ffmpeg.git/tree/doc/APIchanges