Are you hearing a general lack of low frequencies all the time, ie even when the audio is mainly speech etc? In fact the Dolby AC3 spec doesn't include the LFE channel when a player downmixes multichannel audio to stereo. It only includes a baas "boost" but contains no additional information. When downmixing, the LFE channel is actually optional. Given you get the same result when downmixing and converting to AAC, you'd assume it's do with the downmixing and nothing to do with the actual encoding as such. Or maybe if the AC3 dynamic range compression is being applied by one program and not the other. The only thing I could image effecting the presence of low frequencies after downmixing and converting to MP3 would be the inclusion (or not) of the LFE channel. Maybe AC3 isn't a safe bet in the future because it's expensive to integrate in players? PS: I see it's written a lot about AC3 and licensing on the internet. However, I made a test with AC3 sound in mp4 container now, and it played just fine on my stand alone blu-ray player This is because the iPad (Apple) doesn't support AC3 sound (and that's too bad). mp4 with AAC audio mainly because I wanted to watch the video on my iPad and via AppleTV. I don't know what your playback device is, but could you use MKV instead of MP4 containers? Devices that support MKV are generally less fussy than those that support MP4 and H.264 video + AC3 audio should be fine anything that support MKV. It would be better to buy a better playback device, like a Western Digital or similar media streamer, than to have to use MP3 because some old crappy player requires it when it should allow AC3. I think it's very foolish to let a piece of hardware dictate that you convert everything. I guess you did not think about just testing it to see if it works. But it's been years since they changed that to support it. The idiots who wrote the MP4 spec (probably Apple but I truly don't know) did not at first support AC3 audio. But I'm not convinced that you really and truly need to use MP3 either. Is there really a compelling reason that you aren't just using the original audio or maybe extracting AC3 to use instead of MP3? I'm not a big fan of AAC for reasons of compatibility (it's still not as well supported as its fans would like you to think) so I get not using that. Today very large disk drives are cheap, DVD burners are cheap too, and there's no real need for MP3 audio. MP3 was important because it compressed a lot and it was extremely well supported because the licenses were so cheap that all the manufacturers could easily afford to pay the fees to officially and legally support it. If necessary, you may be able to force a higher bitrate by setting the key frame interval to a low number, such as 5 or 2 and also setting the target data rate to a high number, such as 40 Mbps and keep a Variable Bitrate setting.Why are you using MP3 audio? Look, I'm not here to bash you or tell you it's terrible, but it was used years ago as audio for films back in the days when Divx/Xvid was state of the art and DVD drives were too expensive, so people had to put movies on CD-R discs that they converted with Divx/Xvid. We recommend setting a Constant Bitrate during the export process. We recommend using the highest quality source file available to prevent this.Ī low bitrate may also be caused by using Variable Bitrate during the export process. Please note: that re-encoding a low bitrate file or using a low bitrate source will not improve the quality of your spot but it will allow it to pass validation. We have tutorials available that can help you encode your file with an acceptable bitrate. Spots that fall below these bitrate levels will need to be re-encoded with a higher bitrate. To ensure the quality of spots sent from Spotloader we require they maintain an acceptable minimum bitrate determined by their file type. Imperfections in the video called artifacts may also be present in a low bitrate file. When a file’s bitrate is set too low there may not be enough information to accurately reproduce visual elements in the video. In general, a higher bitrate equates to a clearer and sharper image regardless of a spots resolution. Video bitrate is the amount of data contained within each second of video and plays a big role in a file’s visual fidelity.
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