[FFmpeg-devel] [PATCH] Print pixel and screen aspect ratios
Michel Bardiaux
mbardiaux
Thu Oct 18 14:48:31 CEST 2007
Robert Swain a ?crit :
> Hello,
>
> On 18 Oct 2007, at 12:49, Michel Bardiaux wrote:
>> Index: libavcodec/utils.c
>> ===================================================================
>> --- libavcodec/utils.c (revision 10716)
>> +++ libavcodec/utils.c (working copy)
>> @@ -1075,6 +1075,7 @@
>> char buf1[32];
>> char channels_str[100];
>> int bitrate;
>> + AVRational screen_aspect_ratio;
>>
>> if (encode)
>> p = avcodec_find_encoder(enc->codec_id);
>> @@ -1125,6 +1126,14 @@
>> snprintf(buf + strlen(buf), buf_size - strlen(buf),
>> ", %dx%d",
>> enc->width, enc->height);
>> + av_reduce(&screen_aspect_ratio.num,
>> &screen_aspect_ratio.den,
>> + enc->width*enc->sample_aspect_ratio.num,
>> + enc->height*enc->sample_aspect_ratio.den,
>> + 1024*1024);
>> + snprintf(buf + strlen(buf), buf_size - strlen(buf),
>> + " [PAR %d:%d SAR %d:%d]",
>
> SAR is a bad choice of nomenclature, one because everyone else calls
> this the display aspect ratio, as far as I am aware, and two because
> SAR is an abbreviation for an alternative to PAR (pixel vs sample,
> same meaning).
Valid point. DAR it is. New patch attached.
BTW: detecting changes of SAR in the video stream would be good, but (1)
I dont know what would be a good place (avcodec_decode_video?) (2) We
should also detect changes of width, height, since all 3 may change at
anytime in digital-TV streaming (and are likely to when HDTV comes!)
>
>> + enc->sample_aspect_ratio.num, enc-
>>> sample_aspect_ratio.den,
>> + screen_aspect_ratio.num,
>> screen_aspect_ratio.den);
>> if(av_log_level >= AV_LOG_DEBUG){
>> int g= ff_gcd(enc->time_base.num, enc-
>>> time_base.den);
>> snprintf(buf + strlen(buf), buf_size - strlen(buf),
--
Michel Bardiaux
R&D Director
T +32 [0] 2 790 29 41
F +32 [0] 2 790 29 02
E mailto:mbardiaux at mediaxim.be
Mediaxim NV/SA
Vorstlaan 191 Boulevard du Souverain
Brussel 1160 Bruxelles
http://www.mediaxim.com/
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