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media: Update MediaMuxer Java doc to reflect new features.

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Generated a table to summarizes the feature support in different API version
and containers. Features include: Muxing B-frame, 3GP container, multiple
video/audio tracks, metadata tracks.

Test: None as just documentation.
Bug: 28536560
Change-Id: I7ab883a46f4b3420542eae504a33d4ebe1176a65
This commit is contained in:
Hangyu Kuang
2017-02-15 16:15:59 -08:00
parent 1c2beb2eb6
commit 7e2f547da8
1 changed files with 178 additions and 3 deletions
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181
media/java/android/media/MediaMuxer.java
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@@ -32,9 +32,8 @@ import java.nio.ByteBuffer;
import java.util.Map;
/**
* MediaMuxer facilitates muxing elementary streams. Currently supports mp4 or
* webm file as the output and at most one audio and/or one video elementary
* stream. MediaMuxer does not support muxing B-frames.
* MediaMuxer facilitates muxing elementary streams. Currently MediaMuxer supports MP4, Webm
* and 3GP file as the output. It also supports muxing B-frames in MP4 since Android Nougat.
* <p>
* It is generally used like this:
*
@@ -65,6 +64,182 @@ import java.util.Map;
* muxer.stop();
* muxer.release();
* </pre>
*
<h4>Metadata Track</h4>
<p>
Metadata is usefule in carrying extra information that correlated with video or audio to
facilate offline processing, e.g. gyro signals from the sensor. Meatadata track is only
supported in MP4 format. When adding a metadata track, track's mime format must start with
prefix "application/", e.g. "applicaton/gyro". Metadata's format/layout will be defined by
the application. The generated MP4 file uses TextMetaDataSampleEntry defined in section 12.3.3.2
of the ISOBMFF to signal the metadata's mime format. When using {@link android.media.MediaExtractor}
to extract the file with metadata track, the mime format of the metadata will be extracted into
{@link android.media.MediaFormat}.
<pre class=prettyprint>
MediaMuxer muxer = new MediaMuxer("temp.mp4", OutputFormat.MUXER_OUTPUT_MPEG_4);
// More often, the MediaFormat will be retrieved from MediaCodec.getOutputFormat()
// or MediaExtractor.getTrackFormat().
MediaFormat audioFormat = new MediaFormat(...);
MediaFormat videoFormat = new MediaFormat(...);
// Setup Metadata Track
MediaFormat metadataFormat = new MediaFormat(...);
metadataFormat.setString(KEY_MIME, "application/gyro");
int audioTrackIndex = muxer.addTrack(audioFormat);
int videoTrackIndex = muxer.addTrack(videoFormat);
int metadataTrackIndex = muxer.addTrack(metadataFormat);
ByteBuffer inputBuffer = ByteBuffer.allocate(bufferSize);
boolean finished = false;
BufferInfo bufferInfo = new BufferInfo();
muxer.start();
while(!finished) {
// getInputBuffer() will fill the inputBuffer with one frame of encoded
// sample from either MediaCodec or MediaExtractor, set isAudioSample to
// true when the sample is audio data, set up all the fields of bufferInfo,
// and return true if there are no more samples.
finished = getInputBuffer(inputBuffer, sampleType, bufferInfo);
if (!finished) {
int currentTrackIndex = getTrackIndex(sampleType);
muxer.writeSampleData(currentTrackIndex, inputBuffer, bufferInfo);
}
};
muxer.stop();
muxer.release();
}</pre>
<h2 id=History><a name="History"></a>Features and API History</h2>
<p>
The following table summarizes the feature support in different API version and containers.
For API version numbers, see {@link android.os.Build.VERSION_CODES}.
<style>
.api > tr > th, .api > tr > td { text-align: center; padding: 4px 4px; }
.api > tr > th { vertical-align: bottom; }
.api > tr > td { vertical-align: middle; }
.sml > tr > th, .sml > tr > td { text-align: center; padding: 2px 4px; }
.fn { text-align: center; }
</style>
<table align="right" style="width: 0%">
<thead>
<tbody class=api>
<tr><th>Symbol</th>
<th>Meaning</th></tr>
</tbody>
</thead>
<tbody class=sml>
<tr><td>&#9679;</td><td>Supported</td></tr>
<tr><td>&#9675;</td><td>Not supported</td></tr>
<tr><td>&#9639;</td><td>Supported in MP4/WebM/3GP</td></tr>
<tr><td>&#8277;</td><td>Only Supported in MP4</td></tr>
</tbody>
</table>
<table align="center" style="width: 100%;">
<thead class=api>
<tr>
<th rowspan=2>Feature</th>
<th colspan="24">SDK Version</th>
</tr>
<tr>
<th>18</th>
<th>19</th>
<th>20</th>
<th>21</th>
<th>22</th>
<th>23</th>
<th>24</th>
<th>25</th>
<th>26+</th>
</tr>
</thead>
<tbody class=api>
<tr>
<td align="center">MP4 container</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
</tr>
<td align="center">WebM container</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
<td>&#9679;</td>
</tr>
<td align="center">3GP container</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9679;</td>
</tr>
<td align="center">Muxing B-Frames(bi-directional predicted frames)</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#8277;</td>
<td>&#8277;</td>
<td>&#8277;</td>
</tr>
</tr>
<td align="center">Muxing Single Video/Audio Track</td>
<td>&#9639;</td>
<td>&#9639;</td>
<td>&#9639;</td>
<td>&#9639;</td>
<td>&#9639;</td>
<td>&#9639;</td>
<td>&#9639;</td>
<td>&#9639;</td>
<td>&#9639;</td>
</tr>
</tr>
<td align="center">Muxing Multiple Video/Audio Tracks</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#8277;</td>
</tr>
</tr>
<td align="center">Muxing Metadata Tracks</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#9675;</td>
<td>&#8277;</td>
</tr>
</tbody>
</table>
*/
final public class MediaMuxer {