I have a video file encoded with h.264 that will not play on iOS, and I'd like to know why. Here's the HTML:
<video style="width: 480px; height: 360px;" autoplay controls>
<source src="sample.mp4">
</video>
This video plays fine in a desktop browser, but on iOS devices I see an un-clickable Play icon with a slash through it. I've read that this means there's a problem with the video's encoding, but I'm not sure what the problem is.
I ran the video through MediaInfo:
General
Format : MPEG-4
Format profile : Base Media
Codec ID : isom
File size : 706 KiB
Duration : 15s 256ms
Overall bit rate mode : Variable
Overall bit rate : 379 Kbps
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L5.1
Format settings, CABAC : Yes
Format settings, ReFrames : 6 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 15s 250ms
Bit rate : 311 Kbps
Width : 480 pixels
Height : 360 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 24.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.075
Stream size : 578 KiB (82%)
Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 15s 256ms
Bit rate mode : Variable
Bit rate : 62.8 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 117 KiB (17%)
Also, I ran it through GSpot and got some additional info:
Container
isom: MP4 Base Media v1 [IS0 14496-12:2003]
- mp41: MP4 v1 [ISO 14496-1:ch13]
Can anyone tell me why this video won't play? I know I can simply re-encode the video, and if I do, it plays fine on iOS. But I'd like to know what the problem with the original file is.
For comparison, here's the MediaInfo analysis of a re-encoded version I made (this one works):
General
Format : MPEG-4
Format profile : Base Media
Codec ID : isom
File size : 990 KiB
Duration : 15s 256ms
Overall bit rate mode : Variable
Overall bit rate : 532 Kbps
Writing application : Lavf53.19.0
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L2.1
Format settings, CABAC : Yes
Format settings, ReFrames : 4 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 15s 250ms
Bit rate : 414 Kbps
Width : 480 pixels
Height : 360 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 24.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.100
Stream size : 771 KiB (78%)
Writing library : x264 core 118 r2085 8a62835
Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x111 / me=hex / subme=6 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=24 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=22.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 15s 256ms
Bit rate mode : Variable
Bit rate : 111 Kbps
Maximum bit rate : 128 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 207 KiB (21%)
GSpot's info about this one's container is different (could that be why this one works?):
Container
isom: MP4 Base Media v1 [IS0 14496-12:2003]
- iso2: MP4 Base Media v2 [ISO 14496-12:2005]
- avc1: MP4 Base w/ AVC ext [ISO 14496-12:2005]
- mp41: MP4 v1 [ISO 14496-1:ch13]
The only other thing I can think of is the number of reference frames (I've read the max is 3), but the re-encoded version has 4 so I figure that's probably not it.