bldblind
5th July 2007, 22:16
Hi all,
I'm new to encoding and I've got 2 questions.
1. The first issue is about color : after encoding an MPEG2 movie with XVid, I was surprised with the colors of the encoded movie : it was lighter, less brilliant. I tried different player (MPC was the orginal one) but no changes. So I decided to try some other codec (DivX, and AVC x264). Same result. But a raw output (uncompressed) looks like the MPEG2 source. Is there any codec setting that I forgot ? Or my in encoding tools (VirtualDub 1.6) ? I thought that the codec don't operate in the same colorspace but even if they don't use the same 'color model', the result (after a decompression by the player) must be identical. So what's wrong ?
2. The second issue is about quality : the re-encoded result is poor compared to the original (compared to the result movie sample for dynamic view and with a bmp image sequence extraction to see 'pixelisation'). Same thing, I've tried with XVid, DivX, AVC x264 and result are quite similar : not bad but not very good too. I've tried different bitrates(from 1200 up to 4000 kps, no sounds and 2 passes) to attenuate the compression factor. I've also tried to play with codecs settings (optimization, very high quality factor, quarter pixel, motion detection and so on). After reading different things about MPEG4 ASP & AVC, I thought that codec implementations will be more efficient (or equally efficient) than the 'old' MPEG2 codec. But - at the same bitrates than the original - the result is (visibly) degraded
Of course, the result is better than VHS (hehe !) but deceiving related to MPEG2, mainly for bigger screens (projector, big plasma ...). Question : am I wrong with encoding (tools or settings) or does the MPEG4 revolution is just a commercial announcement and good result with MPEG4 will be obtain only with very high end hardware (-> movie studio), as today with MPEG2 ?
Thanks !
I'm new to encoding and I've got 2 questions.
1. The first issue is about color : after encoding an MPEG2 movie with XVid, I was surprised with the colors of the encoded movie : it was lighter, less brilliant. I tried different player (MPC was the orginal one) but no changes. So I decided to try some other codec (DivX, and AVC x264). Same result. But a raw output (uncompressed) looks like the MPEG2 source. Is there any codec setting that I forgot ? Or my in encoding tools (VirtualDub 1.6) ? I thought that the codec don't operate in the same colorspace but even if they don't use the same 'color model', the result (after a decompression by the player) must be identical. So what's wrong ?
2. The second issue is about quality : the re-encoded result is poor compared to the original (compared to the result movie sample for dynamic view and with a bmp image sequence extraction to see 'pixelisation'). Same thing, I've tried with XVid, DivX, AVC x264 and result are quite similar : not bad but not very good too. I've tried different bitrates(from 1200 up to 4000 kps, no sounds and 2 passes) to attenuate the compression factor. I've also tried to play with codecs settings (optimization, very high quality factor, quarter pixel, motion detection and so on). After reading different things about MPEG4 ASP & AVC, I thought that codec implementations will be more efficient (or equally efficient) than the 'old' MPEG2 codec. But - at the same bitrates than the original - the result is (visibly) degraded
Of course, the result is better than VHS (hehe !) but deceiving related to MPEG2, mainly for bigger screens (projector, big plasma ...). Question : am I wrong with encoding (tools or settings) or does the MPEG4 revolution is just a commercial announcement and good result with MPEG4 will be obtain only with very high end hardware (-> movie studio), as today with MPEG2 ?
Thanks !