几年前，我没能转换从 iTunes 购买的受 DRM 保护的 m4p 文件。从我在论坛上看到的内容来看，这曾经是可行的。
ffprobe：
nput #0, mov,mp4,m4a,3gp,3g2,mj2, from '01 Meds (Featuring Alison Mosshart).m4p':
Metadata:
major_brand : M4A
minor_version : 0
compatible_brands: M4A mp42isom
creation_time : 2006-03-02T03:01:35.000000Z
iTunNORM : 00001A4A 00001C50 0000B942 0000CEBE 0002634C 00024ADC 00008000 00008000 0000CFA1 0000C535
tool : ??�
title : Meds (Featuring Alison Mosshart)
artist : Placebo
album : Meds
genre : Rock
track : 1/13
disc : 1/1
date : 2006-03-14T08:00:00Z
account_id :
copyright : ℗ 2006 The copyright in this sound recording is owned by Virgin Records Ltd
rating : 0
album_artist : Placebo
account_type : 0
media_type : 1
purchase_date : 2012-06-22 17:21:52
Duration: 00:02:55.47, start: 0.000000, bitrate: 137 kb/s
Stream #0:0(und): Audio: aac (LC) (drms / 0x736D7264), 44100 Hz, stereo, fltp, 127 kb/s (default)
Metadata:
creation_time : 2006-03-02T03:01:35.000000Z
handler_name : soun
Stream #0:1: Video: mjpeg (Baseline), yuvj444p(pc, bt470bg/unknown/unknown), 600x600 [SAR 72:72 DAR 1:1], 90k tbr, 90k tbn, 90k tbc (attached pic)
ffmpeg -i 输入.m4p 输出.mp3
错误：
[aac @ 0x5578fc676740] Reserved bit set.
[aac @ 0x5578fc676740] TNS filter order 26 is greater than maximum 12.
Error while decoding stream #0:0: Invalid data found when processing input
[aac @ 0x5578fc676740] channel element 2.4 is not allocated
Error while decoding stream #0:0: Invalid data found when processing input
[aac @ 0x5578fc676740] channel element 2.10 is not allocated
Error while decoding stream #0:0: Invalid data found when processing input
[aac @ 0x5578fc676740] Reserved bit set.
[aac @ 0x5578fc676740] Number of scalefactor bands in group (51) exceeds limit (49).
Error while decoding stream #0:0: Invalid data found when processing input
[aac @ 0x5578fc676740] channel element 3.8 is not allocated
Error while decoding stream #0:0: Invalid data found when processing input
[aac @ 0x5578fc676740] Sample rate index in program config element does not match the sample rate index configured by the container.
[aac @ 0x5578fc676740] Inconsistent channel configuration.
[aac @ 0x5578fc676740] get_buffer() failed
Error while decoding stream #0:0: Invalid argument
[aac @ 0x5578fc676740] Number of bands (7) exceeds limit (5).
Error while decoding stream #0:0: Invalid data found when processing input
[aac @ 0x5578fc676740] channel element 2.15 is not allocated
Error while decoding stream #0:0: Invalid data found when processing input
[aac @ 0x5578fc676740] Sample rate index in program config element does not match the sample rate index configured by the container.
[aac @ 0x5578fc676740] Inconsistent channel configuration.
[aac @ 0x5578fc676740] get_buffer() failed
Error while decoding stream #0:0: Invalid argument
[aac @ 0x5578fc676740] channel element 2.4 is not allocated
Error while decoding stream #0:0: Invalid data found when processing input
[aac @ 0x5578fc676740] Prediction is not allowed in AAC-LC.
Error while decoding stream #0:0: Invalid data found when processing input
[aac @ 0x5578fc676740] Sample rate index in program config element does not match the sample rate index configured by the container.
[aac @ 0x5578fc676740] Too large remapped id is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[aac @ 0x5578fc676740] If you want to help, upload a sample of this file to ftp://upload.ffmpeg.org/incoming/ and contact the ffmpeg-devel mailing list. ([email protected])
Error while decoding stream #0:0: Not yet implemented in FFmpeg, patches welcome
[aac @ 0x5578fc676740] Pulse tool not allowed in eight short sequence.
Error while decoding stream #0:0: Invalid data found when processing input
[aac @ 0x5578fc676740] SBR was found before the first channel element.
[aac @ 0x5578fc676740] Reserved bit set.
[aac @ 0x5578fc676740] Prediction is not allowed in AAC-LC.
Error while decoding stream #0:0: Invalid data found when processing input