HNHacker News
TopNewBestAskShowJobs

busup

3 karma · joined December 14, 2023

submissionscomments
busup··on FFmpeg 8.0 adds Whisper support
Maybe try the turbo model which is transcription only. The other models were trained on x to en translations and they seem to emphasise the output language over the task token. You can get them to translate to any language even though it was never trained for that, comparatively nl-en translation is in the dataset so I'm not surprised it's doing that.
busup··on JEDEC Extends DDR5 Memory Spec to 8800 MT/S, Adds Anti-Rowhammer Features
To read a single cache line from DDR4 (basically the same for DDR5 but I'm less familiar) the memory controller needs to:

  1. send ACT
  2. wait tRCD(RD)
  3. send READ
  4. wait tCL
  5. read the burst from the DQ
The original 10ns number was only taking step 4 into account. tRCDRD is just as long if not longer. Then the burst takes a couple more ns.
busup··on Whisper: Nvidia RTX 4090 vs. M1 Pro with MLX
Nice, thanks for your work on everything Whisper related. I tested it a couple weeks ago which largely matched the results in the insanely fast whisper notebook. Comparison was with BetterTransformers.

I just reran the notebook with 4.36.1 (minus the to_bettertransformer line) but it was slower (the batch size 24 section took 8 vs 5 min). Is there something I need to change? Going back to 4.35.2 gives the old numbers so the T4 instance seems fine.

busup··on Whisper: Nvidia RTX 4090 vs. M1 Pro with MLX
It's beam size 1. From my quick tests on a Colab T4, CTranslate2 (faster-whisper's backend) is about 30% faster with like for like settings. I decoded the audio, got mel features, split into 30s segments, and ran it batched (beam size 1, batch size 24, no temperature fallback passes). Takes a bit more effort than a cli utility but isn't too hard.

Side note, the insanely fast whisper readme gives benchmarks on an A100 but only the FA2 lines were. The rest were on a T4 looking at the notebooks/history. Turing doesn't support FA2 so the gap should be smaller with it, but based on the distil-whisper paper CTranslate2 is probably still faster.

TensorRT-LLM might be faster but I haven't looked into it yet.