diff --git a/RELEASENOTES.md b/RELEASENOTES.md index 883862e386c..64a3f7a43a1 100644 --- a/RELEASENOTES.md +++ b/RELEASENOTES.md @@ -507,6 +507,9 @@ This release includes the following changes since the `rowLock` and `columnLock` should both be assumed to be true, regardless of the values present in the stream (`columnLock` support is not implemented, so it's effectively assumed to always be false). + * CEA-708: Avoid duplicate newlines being added by ExoPlayer's naive + handling of the 'set pen location' command + ([#1315](https://github.com/androidx/media/pull/1315)). * Image: * Add support for DASH thumbnails. Grid images are cropped and individual thumbnails are provided to `ImageOutput` close to their presentation diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/text/cea/Cea708Decoder.java b/libraries/extractor/src/main/java/androidx/media3/extractor/text/cea/Cea708Decoder.java index 077d1e2210a..9345b0ea2f3 100644 --- a/libraries/extractor/src/main/java/androidx/media3/extractor/text/cea/Cea708Decoder.java +++ b/libraries/extractor/src/main/java/androidx/media3/extractor/text/cea/Cea708Decoder.java @@ -778,11 +778,9 @@ private void handleDefineWindow(int window) { // first byte captionChannelPacketData.skipBits(2); // null padding boolean visible = captionChannelPacketData.readBit(); - // ANSI/CTA-708-E S-2023 spec (Section 8.4.7) indicates that rowLock and columnLock values in // the media should be ignored and assumed to be true. captionChannelPacketData.skipBits(2); - int priority = captionChannelPacketData.readBits(3); // second byte boolean relativePositioning = captionChannelPacketData.readBit(); @@ -1228,6 +1226,8 @@ public void append(char text) { || rolledUpCaptions.size() >= MAXIMUM_ROW_COUNT) { rolledUpCaptions.remove(0); } + // update row value after newline + row = rolledUpCaptions.size(); } else { captionStringBuilder.append(text); } diff --git a/libraries/extractor/src/test/java/androidx/media3/extractor/text/cea/Cea708DecoderTest.java b/libraries/extractor/src/test/java/androidx/media3/extractor/text/cea/Cea708DecoderTest.java index f4b196c6ec2..28deb05c8df 100644 --- a/libraries/extractor/src/test/java/androidx/media3/extractor/text/cea/Cea708DecoderTest.java +++ b/libraries/extractor/src/test/java/androidx/media3/extractor/text/cea/Cea708DecoderTest.java @@ -118,6 +118,91 @@ public void singleServiceAndWindowDefinition_ignoresRowLock() throws Exception { assertThat(getOnlyCue(result).text.toString()).isEqualTo("row3\nrow4"); } + /** + * ExoPlayer's incomplete implementation of the 'set pen location' command appends a newline if + * the 'new' row location is different to the 'current' row (this is to ensure that subtitles that + * are meant to be on different lines aren't concatenated together on a single line). This test + * demonstrates this, even though the target row is 2, only a single newline is appended. + */ + @Test + public void setPenLocation_appendsNewlineIfRowChanges() throws Exception { + Cea708Decoder cea708Decoder = + new Cea708Decoder( + + /* accessibilityChannel= */ Format.NO_VALUE, /* initializationData= */ null); + byte[] windowDefinition = + TestUtil.createByteArray( + 0x98, // DF0 command (define window 0) + 0b0010_0000, // visible=true, row lock and column lock disabled, priority=0 + 0xF0 | 50, // relative positioning, anchor vertical + 50, // anchor horizontal + 10, // anchor point = 0, row count = 10 + 30, // column count = 30 + 0b0000_1001); // window style = 1, pen style = 1 + byte[] setCurrentWindow = TestUtil.createByteArray(0x80); // CW0 (set current window to 0) + // COMMAND_SPL with row 2 and column 0 + byte[] setPenLocation = TestUtil.createByteArray(0x92, 0x02, 0x00); + byte[] subtitleData = + encodePacketIntoBytePairs( + createPacket( + /* sequenceNumber= */ 0, + createServiceBlock( + Bytes.concat( + windowDefinition, + setCurrentWindow, + "line1".getBytes(Charsets.UTF_8), + setPenLocation, + "line2".getBytes(Charsets.UTF_8))))); + + Subtitle firstSubtitle = decodeSampleAndCopyResult(cea708Decoder, subtitleData); + + assertThat(getOnlyCue(firstSubtitle).text.toString()).isEqualTo("line1\nline2"); + } + + /** + * ExoPlayer's incomplete implementation of the 'set pen location' command appends a newline if + * the 'new' row location is different to the 'current' row (this is to ensure that subtitles that + * are meant to be on different lines aren't concatenated together on a single line). This test + * ensures that if there's already an explicit newline appended before the command, a duplicate + * newline isn't appended. + */ + @Test + public void setPenLocation_explicitNewLineBefore_secondNewlineNotAdded() throws Exception { + Cea708Decoder cea708Decoder = + new Cea708Decoder( + + /* accessibilityChannel= */ Format.NO_VALUE, /* initializationData= */ null); + byte[] windowDefinition = + TestUtil.createByteArray( + 0x98, // DF0 command (define window 0) + 0b0010_0000, // visible=true, row lock and column lock disabled, priority=0 + 0xF0 | 50, // relative positioning, anchor vertical + 50, // anchor horizontal + 10, // anchor point = 0, row count = 10 + 30, // column count = 30 + 0b0000_1001); // window style = 1, pen style = 1 + byte[] setCurrentWindow = TestUtil.createByteArray(0x80); // CW0 (set current window to 0) + // COMMAND_SPL with row 1 and column 0 + byte[] setPenLocation = TestUtil.createByteArray(0x92, 0x01, 0x00); + byte[] newLine = TestUtil.createByteArray(0x0D); // new line + byte[] subtitleData = + encodePacketIntoBytePairs( + createPacket( + /* sequenceNumber= */ 0, + createServiceBlock( + Bytes.concat( + windowDefinition, + setCurrentWindow, + "line1".getBytes(Charsets.UTF_8), + newLine, + setPenLocation, + "line2".getBytes(Charsets.UTF_8))))); + + Subtitle firstSubtitle = decodeSampleAndCopyResult(cea708Decoder, subtitleData); + + assertThat(getOnlyCue(firstSubtitle).text.toString()).isEqualTo("line1\nline2"); + } + /** * Queues {@code sample} to {@code decoder} and dequeues the result, then copies and returns it if * it's non-null.