Incorrect playing of Coub video

Hi all!

### Issue description

I've tried to embed playing of Coub's videos in my app with ExoPlayer and I'm faced with the problem that ExoPlayer incorrectly reports length of those videos and as a consequence fails to loop/replay them.
Coub's videos have video steam only (no audio) coded with H264 and packet into mp4 container.

### Reproduction steps
Add the following to the demo App:
"name": "Misc",
"samples": [
{
"name": "Coub sample",
"uri": "https://coubsecure-s.akamaihd.net/get/b102/p/coub/simple/cw_file/010b9332a46/0ec149d027f8d844f52f8/muted_mp4_med_size_1477783374_muted_med.mp4"
},
]
Expected result:
Reported length of the video is 8 seconds.
The video can be replayed/rewinded.

Actual result:
Reported length of the video is 2 seconds only
The player fails to replay/rewind.

}

### Link to test content

https://coubsecure-s.akamaihd.net/get/b102/p/coub/simple/cw_file/010b9332a46/0ec149d027f8d844f52f8/muted_mp4_med_size_1477783374_muted_med.mp4
https://coubsecure-s.akamaihd.net/get/b175/p/coub/simple/cw_file/54e7b85e97a/07582b3a1d6ae594bac15/muted_mp4_med_size_1499090722_muted_med.mp4
These videos are ripped from standard Coub API, I can provide more samples if needed.

### Version of ExoPlayer being used
2.4.1 & 2.4.3

### Device(s) and version(s) of Android being used
4.4 (Huawei honor)
7.0 (Emulator)

### A full bug report captured from the device

```
--------- beginning of system
07-18 11:45:03.696 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: videoDisabled [90.89]
07-18 11:45:06.077 11469-11469/com.google.android.exoplayer2.demo I/ExoPlayerImpl: Init ExoPlayerLib/2.4.1 [generic_x86, Android SDK built for x86, Google, 24]
07-18 11:45:06.080 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: state [0.00, true, I]
07-18 11:45:06.085 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: state [0.01, true, B]
07-18 11:45:06.086 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: sourceInfo [periodCount=1, windowCount=1
07-18 11:45:06.086 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: period [?]
07-18 11:45:06.086 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: window [?, false, false]
07-18 11:45:06.086 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: ]
07-18 11:45:06.086 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: loading [true]
07-18 11:45:06.160 11469-14960/com.google.android.exoplayer2.demo I/OMXClient: MuxOMX ctor
07-18 11:45:06.175 11469-14959/com.google.android.exoplayer2.demo I/MediaCodec: [OMX.google.h264.decoder] setting surface generation to 11744260
07-18 11:45:06.176 11469-14960/com.google.android.exoplayer2.demo E/ACodec: [OMX.google.h264.decoder] storeMetaDataInBuffers failed w/ err -1010
07-18 11:45:06.215 11469-11496/com.google.android.exoplayer2.demo D/EGL_emulation: eglMakeCurrent: 0xb60050c0: ver 2 0 (tinfo 0xb6003220)
07-18 11:45:06.241 11469-11496/com.google.android.exoplayer2.demo D/EGL_emulation: eglMakeCurrent: 0xb60050c0: ver 2 0 (tinfo 0xb6003220)
07-18 11:45:06.245 11469-14959/com.google.android.exoplayer2.demo D/MediaCodec: [OMX.google.h264.decoder] setting dataspace on output surface to #103
07-18 11:45:06.248 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: sourceInfo [periodCount=1, windowCount=1
07-18 11:45:06.248 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: period [1.92]
07-18 11:45:06.248 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: window [1.92, true, false]
07-18 11:45:06.248 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: ]
07-18 11:45:06.251 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: Tracks [
07-18 11:45:06.251 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: Renderer:0 [
07-18 11:45:06.251 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: Group:0, adaptive_supported=N/A [
07-18 11:45:06.251 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: [X] Track:0, id=1, mimeType=video/avc, res=640x328, supported=YES
07-18 11:45:06.251 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: ]
07-18 11:45:06.251 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: ]
07-18 11:45:06.251 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: ]
07-18 11:45:06.252 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: videoEnabled [0.17]
07-18 11:45:06.252 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: videoFormatChanged [0.17, id=1, mimeType=video/avc, res=640x328]
07-18 11:45:06.268 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: state [0.19, true, R]
07-18 11:45:06.272 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: loading [false]
07-18 11:45:06.273 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: videoDecoderInitialized [0.19, OMX.google.h264.decoder]
07-18 11:45:06.273 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: state [0.19, true, B]
07-18 11:45:06.275 11469-14959/com.google.android.exoplayer2.demo D/SoftwareRenderer: setting dataspace on output surface to #103
07-18 11:45:06.278 11469-11496/com.google.android.exoplayer2.demo D/EGL_emulation: eglMakeCurrent: 0xb60050c0: ver 2 0 (tinfo 0xb6003220)
07-18 11:45:06.296 11469-11496/com.google.android.exoplayer2.demo D/EGL_emulation: eglMakeCurrent: 0xb60050c0: ver 2 0 (tinfo 0xb6003220)
07-18 11:45:06.387 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: renderedFirstFrame [Surface(name=null)/@0xb177275]
07-18 11:45:06.464 11469-11496/com.google.android.exoplayer2.demo D/EGL_emulation: eglMakeCurrent: 0xb60050c0: ver 2 0 (tinfo 0xb6003220)
07-18 11:45:06.477 11469-11496/com.google.android.exoplayer2.demo D/OpenGLRenderer: endAllActiveAnimators on 0xa88acc00 (ExpandableListView) with handle 0x98b16ac0
07-18 11:45:06.495 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: state [0.42, true, R]
07-18 11:45:14.184 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: state [8.11, true, E]
07-18 11:45:14.185 11469-11469/com.google.android.exoplayer2.demo D/EventLogger: droppedFrames [8.11, 1]
```

Thank you in advance.
[bugreport-NYC-2017-07-18-11-44-01.zip](https://github.com/google/ExoPlayer/files/1155314/bugreport-NYC-2017-07-18-11-44-01.zip)