Hello, As of now, avformat_find_info_stream decodes a frame in order to get the codec parameters (width, height, pix_fmt (mandatory) and more depending on the codec) which leads to having images decoded twice.
The following patchset addresses this issue: * by using the AVCodecContext skip_frame field and setting its value to AVDISCARD_ALL in the try_decode_frame function in lavformat/utils.c * by having the decoders interpretting this field a bit more differently: While they are honoring the skip_frame option, they *must* still extract and set the relevant codec parameters to the AVCodecContext. Regarding the last patch which set the avctx->skip_frame to AVDISCARD_ALL, i've choosen to whitelist the codecs that support this behaviour. A blacklist system (that would reflect a todolist) can also be used but it's a bit more risky as we can't miss any codec ids to not break the current probing behaviour. Matthieu _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
