2018-09-01

ポータブルオーディオプレイヤーは二極化している

今のポータブルオーディオプレイヤーは二極化している。格安のゴミみたいな製品と、オーディオフィリ向けのクソみたいな製品があり、その中間がない。

最近、減量のためにジョギングを再開した。ジョギングは一回あたり1時間ほど行うのだが、これが思いの外ヒマだ。この時間を有意義に使いたい。走っている最中にできることは音を聞くぐらいなものだ。音楽に興味はないが英語の朗読を聞くのは有意義なことのように思われる。例えば筆者はまだシェイクスピアのハムレットを読んだことがない。ハムレットを読むには時間がかかるが、ジョギング一回あたりの1時間を使えば、何度か走るだけでシェイクスピアを通して聞くことができる。

そこで早速、ジョージ・オーウェルの1984やシェイクスピアのハムレットを朗読した自由な録音をダウンロードした。

LibriVox

元々が低音質なソースであるのだから、それほど高級な製品はいらない。そこで、アマゾンでよく購入されていた適当な格安ポータブルオーディオプレイヤーであるAGPTEK A01Tと、格安BluetoothイヤホンであるSoundPeats Q30を購入した。

さっそくハムレット朗読のmp3ファイルをコピーするが、なぜか再生の順序がファイル名の文字列順にソートされない。どうやら、FAT32のファイルのディレクトリーエントリーの順番で再生されるようだ。そこで仕方なく、以下のようにして問題を解決した。

ls | while read file ; do mv $file path-to-mp3-storage/$file

いざ聞いてみると、今度は片耳にしか音が聞こえてこない。どうやらこの格安ポータブルオーディオプレイヤーは、モノラルmp3ファイルに対して片耳しか出力しないようだ。残念ながらモノラルmp3ファイルを再エンコードなしでステレオにすることはできないので、以下のようにして無駄にステレオにした。

ls | while read file ;< /dev/null do ffmpeg -i $file -ac 2 -b:a 320k path-to-mp3-storage/$file

当初動かずに困惑したが、ffmpegが標準入力を食べてしまうことが原因だった。

そしてGNU Parallelを使ったほうがよかったことに実行した後に気がついた。

mp3のエンコード速度はそれほどパフォーマンスを重視していない私のラップトップでも175倍速だった。たしか私がmp3プレイヤーを使っていた15年ほど前はせいぜい20倍速に満たない程度だった気がするのだが、いい時代になったものだ。私の一つ上の世代は、mp3をリアルタイムデコードするためにCPUをオーバークロックしたと聞く。

本の朗読を聞くために買ったのだからあまり期待はしていなかったものの、この格安ポータブルオーディオプレイヤーはあまりにもひどい品質だ。おまけに、文字コードの対応もひどい。どうやらいまだにUCSに対応していないらしく、本体の言語設定をした文字に引きづられる。例えば言語をEnglishに設定するとASCII以外が文字化けし、日本語に設定するとシフトJIS外の文字が文字化けするようだ。これは解せない。ファイルシステムであるFAT32はファイル名をUCS-2で管理しているのだから、文字化けを起こすのはわざわざ何かとてもバカなことをしているとしか思えない。

不思議なことに、このポータブルオーディオプレイヤーにはFMラジオとかテキストリーダーとか万歩計とか録音とか動画再生などの様々な機能がありながら、ファイル名によるソート機能すらない。

ではもっとマシなポータブルオーディオプレイヤーはないものか。実は今ポータブルオーディオプレイヤーは二極化しているのだ。

ひとつには私が買ったような数千円で変えるクソのような格安の粗悪品。もう一つには、最低数万円から数十万円もするようなオーディオフィリ向けのバカのような高級品だ。中間層の市場はスマフォが完全に支配してしまったため、ポータブルオーディオプレイヤーは格安と高級品に二極化してしまったのだ。

では高級なポータブルオーディオプレイヤーとはどのようなものだろうか。安いものでも数万円から、高いものになると30万円ぐらいする。30万円だ。嘘ではない。本当だ。曰くハイレゾ、曰く超高性能DAC、曰くUSB Audio/DACに両方とも対応。厳選された高性能で高品質なキャパシタ、コイル、メッキなどなど。

ちょっとまってもらいたい。人間の可聴域は若者でもせいぜい20kHz程度であり、だからこそせいぜい40KHzのサンプリング周波数で20kHzまでの音を再現できるようにしているのだ。ハイレゾに意味はない。USB Audioに対応しているのはともかくとして、なぜUSB DACとして使える必要があるのだ。そして高級なキャパシタやコイルに至っては完全にオーディオフィリの領域だ。

5000円ぐらいでまともなUIを備えたポータブルオーディオプレイヤーはないものか。そもそも格安プレイヤーにすらいらない機能が多すぎる。必要なのはファイル名によるソート、シークバー、Bluetoothだ。自由にプログラミングできればなおよい。

という愚痴を漏らしていると、物好きな同僚がRaspberry Pi Zero WHを進めてきた。初代Raspberry PiのSoCを使い、WiFiとBluetoothが搭載された低電力なボードだ。Raspberry Piはその普及によって圧倒的に自由なソフトウェアスタックを得た。その性能はmp3やoggのリアルタイムデコードを難なくこなせるであろうし、Bluetoothも使える。しかも値段も2千円程度。確かに理想的なポータブルオーディオプレイヤーのように思える。

問題はUIをどうするかだ。タッチパネル付きのディスプレイをつけるのが一番いいように思える。考えてみよう。

68 comments:

Anonymous said...

Rockbox はいかがでしょう。
https://www.rockbox.org/
対応している製品が古めのものが多く、対応製品の入手性はよくなさそうです。
Agptek ではRocker という製品へのポートが行われているようですが、実用性は不明です。
https://www.rockbox.org/dl.cgi?bin=agptekrocker

sportstoto.zone said...

Thank you for sharing this information. I read your blog and I can't stop my self to read your full blog. Again Thanks and Best of luck to your next 토토Blog in future.

baccaratsite.biz said...

It is very well written, and your points are well-expressed. 바카라사이트
I request you warmly, please, don’t ever stop writing.

TOTOSAFEDB33 said...

I think this is an informative post and it is very useful and knowledgeable. therefore, I would like to thank you for the efforts you have made in writing this article.
안전놀이터

toto365.pro said...

온라인카지노 I value the blog article. Thanks Again. Really Great.

toto365.pro said...

토토사이트 I just want to say I’m very new to weblog and seriously loved your web page. More than likely I’m likely to bookmark your blog post . You actually have outstanding stories. Thanks for sharing with us your webpage.

toto365.pro said...

토토사이트 Wow, excellent post. I'd like to draft like this too - taking time and real hard work to make a great article. This post has encouraged me to write some posts that I am going to write soon.

GUIDE1903 said...

I like your post. It is good to see you verbalize from the heart and clarity on this important subject can be easily observed..
한국야동

massage.blue said...

I’m truly enjoying the design and layout of your blog. It’s a very easy on the eyes which makes it much more enjoyable for me to come here and visit more often. Did you hire out a designer to create your theme?

횟수 무제한 출장

magosucomwep said...


Through this post, I know that your good knowledge in playing with all the pieces was very helpful. I notify that this is the first place where I find issues I've been searching for. You have a clever yet attractive way of writing
청마담

magosucowep

baccaratsite.info said...

Remarkable! Its in fact amazing post,Really looking forward to read more. 온라인카지노

casinosite.one said...

I have got much clear idea regarding from this article.I am pleased that I observed this site. 바카라사이트

casinosite.zone said...

Your information was very useful. I m very pleased to read this article. 카지노사이트프로

Voworlds said...



Good web site! I truly love how it is simple on my eyes and the data are well written. I am wondering how I might be notified when a new post has been made. Feel free to visit my website;
오피월드


Anonymous said...


Hello mates, nice piece of writing and fastidious arguments
commented at this place, I am really enjoying by these.
경마사이트

Feel free to visit my blog -

sportstoto365com said...

It's very informative and you are obviously very knowledgeable in this area. You have opened my eyes to varying views on this topic with interesting and solid content. No doubt it is helpful. 토토사이트

bacarasite said...

I truly appreciate basically perusing the majority of your weblogs. I am trying to find issues to improve my website! I assume its good enough to make use of a few of your ideas! 카지노사이트

powerballsite said...

It is amazingly decent to see the best subtle elements introduced in a simple and understanding way. 파워볼사이트

casinosite said...

I require you to thank for your period of this extraordinary read !!! I definitely welcome every last bit of it and I have you bookmarked to take a gander at new stuff of your blog a certain prerequisite read blog! 바카라사이트

TOTOSITEWEB33 said...

Your good writing makes many people feel happy.
With a lot of writing, you are moved a lot. I also have a lot of interactions with you 스포츠토토

GUIDE1903 said...

I want to feel alive and be happy, saying that I will be a good friend with you, and I will be very happy too. I hope there are always good things and happy days. I always cheered for you.
Thank you
일본야동

Voworlds said...

Thanks to my father who shared with me regarding this web site, this weblog
is actually amazing 오피월드

oncagosu said...

Awesome post, you have pointed out some incredible focuses , I in like manner think this s an exceptionally brilliant site. 파워볼


메이저놀이터추천 said...

You are really a genius. I also run a blog, but I don't have genius skills like you. However, I am also writing hard. If possible, please visit my blog and leave a comment. Thank you. 메이저놀이터추천


casino said...

I'm so happy to finally find a post with what I want. casino You have inspired me a lot. If you are satisfied, please visit my website and leave your feedback.


powerball365.info said...

It’s impressive that you are getting thoughts from this piece of writing as well as from our discussion made at this time.파워볼

reelgame.site said...

When I initially left a comment I appear to have clicked the -Notify me when new comments are added- checkbox and now each time a comment is added I receive four emails with the exact same comment. 슬롯머신

메이저놀이터 said...

This is a very impressive subject. Thank you for always. I have been reading your article interestingly. If possible, please visit my website to read my posts and leave comments. Have a nice day! 메이저놀이터 What you wrote was very helpful to me. Thank you. Actually, I run a site similar to you. If you have time, could you visit my site? Please leave your comments after reading what I wrote. If you do so, I will actively reflect your opinion. I think it will be a great help to run my site. Have a good day.


메이저사이트 said...

I finally found what I was looking for! I'm so happy. 메이저사이트


casinosite.zone said...

This post provides clear idea in favor of the new people of blogging, that really how to do blogging and site-building. 카지노사이트프로

ayan said...

I really like your take on the issue. I now have a clear idea on what this matter is all about.. 먹튀검증

ayan said...

You make so many great points here that I read your article a couple of times. Your views are in accordance with my own for the most part. This is great content for your readers. 토토사이트

ayan said...

Wow, What a Excellent post. I really found this to much informatics. It is what i was searching for.I would like to suggest you that please keep sharing such type of info.Thanks 바카라사이트

UNKNOWN said...

I found so many interesting stuff in your blog especially its discussion. From the tons of comments on your articles, I guess I am not the only one having all the enjoyment here! keep up the good work... 백링크

ayan said...

An interesting dialogue is price comment. I feel that it is best to write more on this matter, it may not be a taboo topic however usually individuals are not enough to talk on such topics. To the next. Cheers. Hair transplant cost in Turkey

UNKNOWN said...

This is such a great resource that you are providing and you give it away for free. 구글상위노출

ayan said...

Great write-up, I am a big believer in commenting on blogs to inform the blog writers know that they’ve added something worthwhile to the world wide web!.. Webshop SEO

toto graph said...

My partner and I stumbled over here different web page and thought I might as well check things out. I like what I see so now i am following you. Look forward to exploring your web page repeatedly. 온라인바카라

Anonymous said...

We still cannot quite believe that I was able to often be any type of those staring at the important points located on your blog post. 메이저토토

Anonymous said...

Nice information, valuable and 스포츠토토분석 information and it is also very well written. I will bookmark and comeback soon

Anonymous said...

Some really nice and useful information on this site, besides I believe the style
and design has good features. 토토사이트

Anonymous said...

They were active listeners and viewed meetings deadlines as an imperative. 토토사이트검증

SAFETOTOSITEPRO18 said...

I was reading some of your articles on this website and I conceive this web site is very instructive. 토토

SAFETOTOSITEPRO18 said...

You have some quality information here that any reader would enjoy Keep it up. I would love to see your next update. 바카라사이트

SAFETOTOSITEPRO18 said...

Really appreciate this wonderful post that you have provided for us. Great site and a great topic as well. 파워볼

toto graph said...

We absolutely love your blog and find a lot of your post’s to be exactly what I’m looking for. Does one offer guest writers to write content for yourself? I wouldn’t mind creating a post or elaborating on a few of the subjects you write in relation to here. Again, awesome blog! 해시게임

alone said...

site1518

ayan said...

Someone Sometimes with visits your blog regularly and recommended it in my experience to read as well. The way of writing is excellent and also the content is top-notch. Thanks for that insight you provide the readers! 노원출장마사지

Anonymous said...

I felt extraordinarily upbeat while perusing this web page. This become honestly highly educational website online for me. I definitely favored it. This became actually a welcoming submit. An awful lot preferred! Thanks again for all the information you distribute,right publish. I was very inquisitive about the thing, it's pretty inspiring i ought to admit. I love touring you web site since i always come upon exciting articles like this one. Amazing task, i greatly appreciate that. Do maintain sharing! Regards . Positive website, wherein did u come up with the information in this posting? I've read the various articles to your internet site now, and that i definitely like your fashion. Thank you one million and please maintain up the effective paintings. A very first rate web page. 안전놀이터

Unknown said...

This post gives truly quality information. I am already done it and find that this post is really amazing. Thank you for this brief explanation and very nice information. Keep up the good works. Favorable website, where did u develop the info on this posting? I have actually read a few of the write-ups on your internet site now, and I truly like your design. Many thanks a million as well as please maintain the effective job. You provide very useful data. This post gives me lots of advise it is very useful for me. It helps me very much to solve some problems. Thanks for sharing. I love what you guys are up too. Such clever work and exposure! Keep up the very good works guys . 파워사다리

Anonymous said...

For older parents, retirement or a large promotion at paintings is a time whilst celebration events are going to be a notable idea. Wonderful know-how. With thanks. That is a extremely good platform. I also give you an article about fortnite. Essentially, it's far a pc recreation. It gives a brand new pores and skin to your favorite characters. Get this skins with skin generator. Revel in your fortnite enjoy. Thank you. This is such a notable resource that you are offering and you give it away without cost. I like seeing blog that recognize the cost of supplying a quality useful resource for free. I assume this is an informative put up and it's far very beneficial and knowledgeable. I simply tripped upon your blog and ached to mention that i have absolutely loved reading your blog submit. Thank you for sharing. You've got stated very interesting information ! Ps first rate web page. fantastic goods from you, guy. I have apprehend your stuff previous to and you are just too outstanding. I clearly like what you’ve obtained here, surely like what you’re saying and the way in that you say it. 꽁머니

Johnatan said...

You provide very useful data. This post gives me lots of advise it is very useful for me. It helps me very much to solve some problems. Thanks for sharing. Very informative article. Such an amazing and helpful post. I hope that you continue to do your work like this in the future also. Thanks for sharing. I value this article for the well-researched web content and outstanding wording. I obtained so curious about this product that I couldn't quit reviewing. Your blog site is actually outstanding. I just wanted to give you a heads up! I think your blog may be having internet browser compatibility issues. I must say we should have an online discussion on this. Thanks for participating with us a piece of great information that is actually helpful. 해외배팅사이트

Unknown said...

Wow, What a Excellent post. I really found this to much informatics. It is what i was searching for.I would like to suggest you that please keep sharing such type of info.Thanks. Nice post author. Thank you. Keep it up.This article is very informative. It is very useful for me.Kindly share more articles with me. I shall be very thankful to you. This particular papers fabulous, and My spouse and i enjoy each of the perform that you have placed into this. I’m sure that you will be making a really useful place. I has been additionally pleased. Good perform! I extremely enjoyed the standard information an individual provide for your visitors? Is gonna be back frequently in order to inspect new posts 안전놀이터

Anonymous said...

Thanks for sharing this information. I really like your blog post very much. You have really shared a informative and interesting blog post . It’s difficult to get knowledgeable individuals during this topic, however, you seem like what happens you are referring to! Thanks . Nice post. I discover some thing tougher on distinct blogs everyday. It will always be stimulating to read content from other writers and employ something there. I’d would prefer to apply certain with the content on my own weblog whether you don’t mind. Natually I’ll provide a link on your internet weblog. Appreciate your sharing. fantastic points altogether, you simply received emblem reader. 먹튀검증커뮤니티

Royalcasino912 said...

Royalcasino912

oncasino said...

oncasino

bacarasite.info said...

The details mentioned within the write-up are a number of the top accessible 카지노사이트

reelgame.site said...

Your information was very useful to me. That's exactly what I've been looking for 파친코사이트

casinositenet.com said...

Pretty! This was a really wonderful post. Thank you for your provided information. 카지노

casinositeone.JDS said...


Your website is really cool and this is a great inspiring article.

casinosite777top.JDS said...

Nice post. It is really interesting.

casinositeguidecom.JDS said...

Thanks for sharing the post!

safetotositepro.JDS said...


Nice information, you write very nice articles, I visit your website for regular updates.

totosafesite said...

It is always so interesting to visit your site. What a great information, thanks for sharing

texasholdemsite said...

Nice information. I’ve bookmarked your site, and I’m adding your RSS feeds to my Google account to get updates instantly.

casinositerank said...

I want to to thank you for this good read!! I definitely enjoyed every little bit of it.

gwolf said...


Thanks for sharing this piece of information. I really enjoyed it. keep up the good work.

sportstoto365 said...


this is the best way to share the great article with everyone one, so that everyone can able to utilize this information