Search the Community

Camera encoding noticeably poorer than YouTube encoding at same nominal bitrate I was recently puzzled by the fact that subjectively the sound quality I could get from a camera recording made with the AAC sound codec at a nominal bitrate of 128kbps approx was not as good as the sound quality from a YouTube file streaming with the same audio codec and at the same nominal audio bitrate. (To test the camera, a high quality stereo audio signal was fed to the external microphone socket, at an appropriate level, with the camera's automatic gain control disabled.) I discovered from examining audio bitrate variations as the files were playing that my Panasonic Lumix DMC-G7 camera keeps the recording audio bitrate within a fairly narrow range whereas YouTube videos involve higher peaks in the audio bitrate. (The camera needs to process on the fly. Youtube encoding is an off-line process.) I felt the disparity had been explained. YouTube practices regarding AAC audio bitrate In my internet searches about YouTube bitrates I'd noticed that although these days the AAC audio stream for a 720p YouTube video is generally streamed at a nominal 128kbps there have been differences of opinion regarding what bitrates have been used in the last year or so, and also differences of opinion regarding the subjective quality of the AAC audio. See for example this thread on another forum: and this more recent thread: https://www.reddit.com/r/youtube/comments/6a8a87/request_to_the_dev_team_on_youtube_we_can_tell/ Test upload [only in draft form, and unlisted] In the last week I decided to upload my own very brief 1080p video file to YouTube, with a high audio quality sound stream (44.1kHz, 24-bit, LPCM), to see what YouTube would do with it. I found the results were quite interesting. For the highest resolution video version (1080p), YouTube compressed the sound to a nominal 128kbps AAC stream. However for a lesser video quality version (720p), YouTube compressed the sound to a nominal 192kbps AAC stream. For a lot of music, a nominal 128kbps YouTube stream may sound reasonable enough. However I had chosen a demanding sound track, the FLAC version of a professional closely miked recording of a string quartet. The 192kbps version of this demanding music was definitely better sounding for my ears than the 128kbps version, and the video quality at 720p was quite adequate. Firefox add-on I've found a Firefox Browser add-on that allows the available audio codecs and nominal bitrates of a YouTube title to be examined. This could be used to help identify the best audio stream. Here is a link to the add-on: https://addons.mozilla.org/en-us/firefox/addon/youtube-video-and-audio-dow/ From some spot checking I've done, and as a general statement, it would appear that if a 192kbps AAC audio stream is available, it is usually associated with a 720p video stream, not a 1080p video stream.