Support parsing of sgpd and sbgp boxes

Support parsing of sgpd and sbgp boxes

sgpd: SampleGroupDescription
sbgp: SampleToGroup

Required for key rotation support.

BUG=367366
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=268901

[kqyang, 2014-05-01 17:23:11]

Please review

[xhwang, 2014-05-01 19:11:28]

Generally looks good. My only complain is that I feel we don't have enough
comments/docs in this file/CL so that a person with a copy of the spec could
easily understand the implementation.

https://codereview.chromium.org/260963002/diff/1/media/formats/mp4/box_defini...
File media/formats/mp4/box_definitions.cc (right):

https://codereview.chromium.org/260963002/diff/1/media/formats/mp4/box_defini...
media/formats/mp4/box_definitions.cc:868: }
Why can't we use MaybeReadChild? Is it because there could be multiple sbgp or
sgpd boxes with other grouping types? It may worth some comments to explain why.

https://codereview.chromium.org/260963002/diff/1/media/formats/mp4/box_defini...
File media/formats/mp4/box_definitions.h (right):

https://codereview.chromium.org/260963002/diff/1/media/formats/mp4/box_defini...
media/formats/mp4/box_definitions.h:367: struct MEDIA_EXPORT
SampleGroupDescription : Box {
Add comment that this is "sgpd" box.

https://codereview.chromium.org/260963002/diff/1/media/formats/mp4/box_defini...
media/formats/mp4/box_definitions.h:384: struct MEDIA_EXPORT SampleToGroup : Box
{
Add comment that this is a "sbgp" box.

[kqyang, 2014-05-01 20:26:35]

PTAL

https://codereview.chromium.org/260963002/diff/1/media/formats/mp4/box_defini...
File media/formats/mp4/box_definitions.cc (right):

https://codereview.chromium.org/260963002/diff/1/media/formats/mp4/box_defini...
media/formats/mp4/box_definitions.cc:868: }
On 2014/05/01 19:11:28, xhwang wrote:
> Why can't we use MaybeReadChild? Is it because there could be multiple sbgp or
> sgpd boxes with other grouping types? It may worth some comments to explain
why.

Yes, MaybeReadChild does not tell us whether it reads successfully or it returns
true because there are no more child boxes.

Added more comments explaining it.

https://codereview.chromium.org/260963002/diff/1/media/formats/mp4/box_defini...
File media/formats/mp4/box_definitions.h (right):

https://codereview.chromium.org/260963002/diff/1/media/formats/mp4/box_defini...
media/formats/mp4/box_definitions.h:367: struct MEDIA_EXPORT
SampleGroupDescription : Box {
On 2014/05/01 19:11:28, xhwang wrote:
> Add comment that this is "sgpd" box.

Done.

https://codereview.chromium.org/260963002/diff/1/media/formats/mp4/box_defini...
media/formats/mp4/box_definitions.h:384: struct MEDIA_EXPORT SampleToGroup : Box
{
On 2014/05/01 19:11:28, xhwang wrote:
> Add comment that this is a "sbgp" box.

Done.

[xhwang, 2014-05-01 20:53:33]

lgtm % nit

https://codereview.chromium.org/260963002/diff/40001/media/formats/mp4/box_de...
File media/formats/mp4/box_definitions.cc (right):

https://codereview.chromium.org/260963002/diff/40001/media/formats/mp4/box_de...
media/formats/mp4/box_definitions.cc:862: // is 'seig'. Continue reading until
'seig' is found, or until run out of
s/run/running

[kqyang, 2014-05-06 22:13:01]

https://codereview.chromium.org/260963002/diff/40001/media/formats/mp4/box_de...
File media/formats/mp4/box_definitions.cc (right):

https://codereview.chromium.org/260963002/diff/40001/media/formats/mp4/box_de...
media/formats/mp4/box_definitions.cc:862: // is 'seig'. Continue reading until
'seig' is found, or until run out of
On 2014/05/01 20:53:34, xhwang wrote:
> s/run/running

Done.

[kqyang, 2014-05-07 17:49:25]

The CQ bit was checked by kqyang@chromium.org

[commit-bot: I haz the power, 2014-05-07 17:50:19]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/kqyang@chromium.org/260963002/60001

[commit-bot: I haz the power, 2014-05-07 19:42:02]

Change committed as 268901