Multiformat 128 kbps Listening Test
Reply #47 – 2005-11-14 09:13:39
The closest preset I found was the VBR/Stereo - Internet 90-100 kbps [LC AAC]. On my test tracks, this provided an average bitrate of 133kbps. Some may consider this too far from the target bitrate, but I do believe it is probably not possible to get closer to the target of 128kbps. [a href="index.php?act=findpost&pid=341501"][{POST_SNAPBACK}][/a] I got 125,7 kbps for Nero Digital -internet high with my 150 reference tracks. For the samples "non-classical" samples, I got 133 kbps with the same setting. Note if iTunes will be tested in VBR mode, there will be the same issue. iTunes AAC works as iTunes MP3 in VBR mode: the target bitrate also corresponds to the minimal bitrate. In other words, the encoder don't encode anything below 128 kbps (apart digital silence maybe). Consequently, the bitrate is necessary superior to 128 kbps. I got 133.33 kbps for classical and 137.x for non-classical. Same issue will occur with LAME -V5. Only exception is aoTuV, which benefits for a very flexible VBR mode. These problems might be a good reason to discard all CBR encoder from the test and to use VBR encodings only outputting to the same approximate bitrate. LAME -V5, iTunes AAC and Nero Digital are fortunately is this case. Same for Vorbis of course. I'm not sure that WMA VBR (Std and Pro) could be close to ~130 kbps. If they're not, it may end the debate about using or not this format in the test. kl33per, or someone else, could you try different WMA settings to see if a 1-pass VBR mode could stay close to 130-135 kbps?
Wavpack Hybrid: one encoder, one encoding for all scenarios WavPack -c4.5hx6 (44100Hz & 48000Hz) ≈ 390 kbps + correction file WavPack -c4hx6 (96000Hz) ≈ 768 kbps + correction file WavPack -h (SACD & DSD) ≈ 2400 kbps at 2.8224 MHz