I stripped one of these m4a files into a raw audio file, and then re-encoded it to .m4a to strip any unusual metadata, images, etc... created a dummy .rss feed and it was able to play on podbird... however, the process of stripping down to PCM audio revealed the nature of the unexpected metadata.
It appears to contain Metadata including Chapter information for each track in the mix, as well as subtitles, and mjpeg video streams.. it's made with garageband, so perhaps if someone has that software they could see what data/images are actually there.
That said, it plays fine in every other player I've ever seen!
Metadata:
major_brand : M4A
minor_version : 1
compatible_brands: M4A mp42isom
creation_time : 2015-06-29 17:05:42
composer : Above & Beyond
title : ABGT137
artist : Above & Beyond
album : Group Therapy
encoder : GarageBand 6.0.5
Duration: 02:00:00.16, start: 0.000000, bitrate: 194 kb/s
Chapter #0.0: start 0.000000, end 357.100000
Metadata:
title : 1. Jason Ross ‘Ravenna’ (Anjunabeats)
Chapter #0.1: start 357.100000, end 627.091667
Metadata:
title : 2. Sound Quelle & Max Meyer ‘Monolith’ (Statement)
Chapter #0.2: start 627.091667, end 880.450000
Metadata:
title : 3. BT & Super8 & Tab ‘Aika’ (Anjunabeats)
Chapter #0.3: start 880.450000, end 1201.850000
Metadata:
title : 4. ilan Bluestone ‘Bonsai’ (Anjunabeats) - Record Of The Week
Chapter #0.4: start 1201.850000, end 1460.441667
Metadata:
title : 5. Sub Question ’Semiconductor’ (Elliptical Sun)
Chapter #0.5: start 1460.441667, end 1684.766667
Metadata:
title : 6. Intrinity feat. Erika Faries ‘Don’t Look Back’ [Proglifter Dub Remix] (PHW)
Chapter #0.6: start 1684.766667, end 1971.325000
Metadata:
title : 7. Otto Knows ‘Next To Me’ [Grum Remix] (Big Beat)
Chapter #0.7: start 1971.325000, end 2181.333333
Metadata:
title : 8. Pierce Fulton ‘In Reality’ (White)
Chapter #0.8: start 2181.333333, end 2515.751667
Metadata:
title : 9. Third Party feat. Daniel Gidlund ‘Collide’ (Release)
Chapter #0.9: start 2515.751667, end 2748.236667
Metadata:
title : 10. Cuebrick ‘Demon’ [Kago Pengchi Remix] (Enhanced)
Chapter #0.10: start 2748.236667, end 3033.583333
Metadata:
title : 11. Las Salinas ‘London’ (Vandit)
Chapter #0.11: start 3033.583333, end 3338.591667
Metadata:
title : 12. Cosmic Gate & Mike Schmid ‘No One Can Touch You Now’ [Rodg Remix] (Wake Your Mind)
Chapter #0.12: start 3338.591667, end 3593.911667
Metadata:
title : 13. Jean-Michel Jarre & M83 ‘Glory’ [Steve Angello Remix] (White)
Chapter #0.13: start 3593.911667, end 3882.693333
Metadata:
title : 14. Above & Beyond feat. Zoë Johnston ‘Peace Of Mind’ [Arty Remix] (Anjunabeats) - Push The Button
Chapter #0.14: start 3882.693333, end 4140.643333
Metadata:
title : 15. Max Freegrant & Digital Sketch ‘Counting Down The Days’ (Freegrant)
Chapter #0.15: start 4140.643333, end 4450.328333
Metadata:
title : 16. Mark Knight ’Second Story’ (Suara)
Chapter #0.16: start 4450.328333, end 4767.750000
Metadata:
title : 17. Dusky ‘Skin Deep’ (17 Steps)
Chapter #0.17: start 4767.750000, end 5100.041667
Metadata:
title : 18. Ashworth ‘Cork’ (Needwant)
Chapter #0.18: start 5100.041667, end 5365.936667
Metadata:
title : 19. M83 ‘Midnight City’ [Eric Prydz Private Remix] (Mute) - Flashback
Chapter #0.19: start 5365.936667, end 5637.111667
Metadata:
title : 20. Erkka ‘ID’ (White) - Guest Mix
Chapter #0.20: start 5637.111667, end 6011.361667
Metadata:
title : 21. Erkka ‘Talk To The Hand’ (Anjunadeep) - Guest Mix
Chapter #0.21: start 6011.361667, end 6319.386667
Metadata:
title : 22. Erkka ‘Plastic Flamingos’ (White) - Guest Mix
Chapter #0.22: start 6319.386667, end 6665.016667
Metadata:
title : 23. Erkka ‘ID’ (White) - Guest Mix
Chapter #0.23: start 6665.016667, end 7200.158333
Metadata:
title : 24. Erkka ‘Museme’ (Anjunadeep) - Guest Mix
Stream #0.0(eng): Subtitle: tx3g / 0x67337874, 0 kb/s
Metadata:
creation_time : 2015-06-29 17:05:42
Stream #0.1(eng): Audio: aac, 44100 Hz, stereo, fltp, 191 kb/s (default)
Metadata:
creation_time : 2015-06-29 17:05:42
Stream #0.2(eng): Video: mjpeg, yuvj444p, 300x300 [PAR 72:72 DAR 1:1], 0 kb/s, 600 tbn (default)
Metadata:
creation_time : 2015-06-29 17:05:42
Stream #0.3: Video: mjpeg, yuvj420p, 300x300 [PAR 72:72 DAR 1:1], 90k tbn
I stripped one of these m4a files into a raw audio file, and then re-encoded it to .m4a to strip any unusual metadata, images, etc... created a dummy .rss feed and it was able to play on podbird... however, the process of stripping down to PCM audio revealed the nature of the unexpected metadata.
It appears to contain Metadata including Chapter information for each track in the mix, as well as subtitles, and mjpeg video streams.. it's made with garageband, so perhaps if someone has that software they could see what data/images are actually there.
That said, it plays fine in every other player I've ever seen!
Metadata: brands: M4A mp42isom
major_brand : M4A
minor_version : 1
compatible_
creation_time : 2015-06-29 17:05:42
composer : Above & Beyond
title : ABGT137
artist : Above & Beyond
album : Group Therapy
encoder : GarageBand 6.0.5
Duration: 02:00:00.16, start: 0.000000, bitrate: 194 kb/s
Chapter #0.0: start 0.000000, end 357.100000
Metadata:
title : 1. Jason Ross ‘Ravenna’ (Anjunabeats)
Chapter #0.1: start 357.100000, end 627.091667
Metadata:
title : 2. Sound Quelle & Max Meyer ‘Monolith’ (Statement)
Chapter #0.2: start 627.091667, end 880.450000
Metadata:
title : 3. BT & Super8 & Tab ‘Aika’ (Anjunabeats)
Chapter #0.3: start 880.450000, end 1201.850000
Metadata:
title : 4. ilan Bluestone ‘Bonsai’ (Anjunabeats) - Record Of The Week
Chapter #0.4: start 1201.850000, end 1460.441667
Metadata:
title : 5. Sub Question ’Semiconductor’ (Elliptical Sun)
Chapter #0.5: start 1460.441667, end 1684.766667
Metadata:
title : 6. Intrinity feat. Erika Faries ‘Don’t Look Back’ [Proglifter Dub Remix] (PHW)
Chapter #0.6: start 1684.766667, end 1971.325000
Metadata:
title : 7. Otto Knows ‘Next To Me’ [Grum Remix] (Big Beat)
Chapter #0.7: start 1971.325000, end 2181.333333
Metadata:
title : 8. Pierce Fulton ‘In Reality’ (White)
Chapter #0.8: start 2181.333333, end 2515.751667
Metadata:
title : 9. Third Party feat. Daniel Gidlund ‘Collide’ (Release)
Chapter #0.9: start 2515.751667, end 2748.236667
Metadata:
title : 10. Cuebrick ‘Demon’ [Kago Pengchi Remix] (Enhanced)
Chapter #0.10: start 2748.236667, end 3033.583333
Metadata:
title : 11. Las Salinas ‘London’ (Vandit)
Chapter #0.11: start 3033.583333, end 3338.591667
Metadata:
title : 12. Cosmic Gate & Mike Schmid ‘No One Can Touch You Now’ [Rodg Remix] (Wake Your Mind)
Chapter #0.12: start 3338.591667, end 3593.911667
Metadata:
title : 13. Jean-Michel Jarre & M83 ‘Glory’ [Steve Angello Remix] (White)
Chapter #0.13: start 3593.911667, end 3882.693333
Metadata:
title : 14. Above & Beyond feat. Zoë Johnston ‘Peace Of Mind’ [Arty Remix] (Anjunabeats) - Push The Button
Chapter #0.14: start 3882.693333, end 4140.643333
Metadata:
title : 15. Max Freegrant & Digital Sketch ‘Counting Down The Days’ (Freegrant)
Chapter #0.15: start 4140.643333, end 4450.328333
Metadata:
title : 16. Mark Knight ’Second Story’ (Suara)
Chapter #0.16: start 4450.328333, end 4767.750000
Metadata:
title : 17. Dusky ‘Skin Deep’ (17 Steps)
Chapter #0.17: start 4767.750000, end 5100.041667
Metadata:
title : 18. Ashworth ‘Cork’ (Needwant)
Chapter #0.18: start 5100.041667, end 5365.936667
Metadata:
title : 19. M83 ‘Midnight City’ [Eric Prydz Private Remix] (Mute) - Flashback
Chapter #0.19: start 5365.936667, end 5637.111667
Metadata:
title : 20. Erkka ‘ID’ (White) - Guest Mix
Chapter #0.20: start 5637.111667, end 6011.361667
Metadata:
title : 21. Erkka ‘Talk To The Hand’ (Anjunadeep) - Guest Mix
Chapter #0.21: start 6011.361667, end 6319.386667
Metadata:
title : 22. Erkka ‘Plastic Flamingos’ (White) - Guest Mix
Chapter #0.22: start 6319.386667, end 6665.016667
Metadata:
title : 23. Erkka ‘ID’ (White) - Guest Mix
Chapter #0.23: start 6665.016667, end 7200.158333
Metadata:
title : 24. Erkka ‘Museme’ (Anjunadeep) - Guest Mix
Stream #0.0(eng): Subtitle: tx3g / 0x67337874, 0 kb/s
Metadata:
creation_time : 2015-06-29 17:05:42
Stream #0.1(eng): Audio: aac, 44100 Hz, stereo, fltp, 191 kb/s (default)
Metadata:
creation_time : 2015-06-29 17:05:42
Stream #0.2(eng): Video: mjpeg, yuvj444p, 300x300 [PAR 72:72 DAR 1:1], 0 kb/s, 600 tbn (default)
Metadata:
creation_time : 2015-06-29 17:05:42
Stream #0.3: Video: mjpeg, yuvj420p, 300x300 [PAR 72:72 DAR 1:1], 90k tbn