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author | Andreas Huber <andih@google.com> | 2013-03-25 17:24:23 +0000 |
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committer | Android (Google) Code Review <android-gerrit@google.com> | 2013-03-25 17:24:23 +0000 |
commit | 2850e41813c2bfaf199fefc990d7ec91551a9460 (patch) | |
tree | e4804318faf1b4a6a879ff36c98ff15967d38385 /media | |
parent | a97d15e2e2f0b317a345d3a6f02df80b8988b1f6 (diff) | |
parent | 820ebf8d452165d9a7619e2667ffa3c0b638da39 (diff) | |
download | frameworks_av-2850e41813c2bfaf199fefc990d7ec91551a9460.zip frameworks_av-2850e41813c2bfaf199fefc990d7ec91551a9460.tar.gz frameworks_av-2850e41813c2bfaf199fefc990d7ec91551a9460.tar.bz2 |
Merge "Ensure that the payload in each TS packet is an even multiple of 16 bytes long" into jb-mr2-dev
Diffstat (limited to 'media')
-rw-r--r-- | media/libstagefright/wifi-display/source/TSPacketizer.cpp | 201 |
1 files changed, 158 insertions, 43 deletions
diff --git a/media/libstagefright/wifi-display/source/TSPacketizer.cpp b/media/libstagefright/wifi-display/source/TSPacketizer.cpp index d993764..2c4a373 100644 --- a/media/libstagefright/wifi-display/source/TSPacketizer.cpp +++ b/media/libstagefright/wifi-display/source/TSPacketizer.cpp @@ -502,16 +502,121 @@ status_t TSPacketizer::packetize( // reserved = b1 // the first fragment of "buffer" follows + // Each transport packet (except for the last one contributing to the PES + // payload) must contain a multiple of 16 bytes of payload per HDCP spec. + bool alignPayload = + (mFlags & (EMIT_HDCP20_DESCRIPTOR | EMIT_HDCP21_DESCRIPTOR)); + + /* + a) The very first PES transport stream packet contains + + 4 bytes of TS header + ... padding + 14 bytes of static PES header + PES_private_data_len + 1 bytes (only if PES_private_data_len > 0) + numStuffingBytes bytes + + followed by the payload + + b) Subsequent PES transport stream packets contain + + 4 bytes of TS header + ... padding + + followed by the payload + */ + size_t PES_packet_length = accessUnit->size() + 8 + numStuffingBytes; if (PES_private_data_len > 0) { PES_packet_length += PES_private_data_len + 1; } - size_t numTSPackets; - if (PES_packet_length <= 178) { - numTSPackets = 1; - } else { - numTSPackets = 1 + ((PES_packet_length - 178) + 183) / 184; + size_t numTSPackets = 1; + + { + // Make sure the PES header fits into a single TS packet: + size_t PES_header_size = 14 + numStuffingBytes; + if (PES_private_data_len > 0) { + PES_header_size += PES_private_data_len + 1; + } + + CHECK_LE(PES_header_size, 188u - 4u); + + size_t sizeAvailableForPayload = 188 - 4 - PES_header_size; + size_t numBytesOfPayload = accessUnit->size(); + + if (numBytesOfPayload > sizeAvailableForPayload) { + numBytesOfPayload = sizeAvailableForPayload; + + if (alignPayload && numBytesOfPayload > 16) { + numBytesOfPayload -= (numBytesOfPayload % 16); + } + } + + // size_t numPaddingBytes = sizeAvailableForPayload - numBytesOfPayload; + ALOGV("packet 1 contains %zd padding bytes and %zd bytes of payload", + numPaddingBytes, numBytesOfPayload); + + size_t numBytesOfPayloadRemaining = accessUnit->size() - numBytesOfPayload; + +#if 0 + // The following hopefully illustrates the logic that led to the + // more efficient computation in the #else block... + + while (numBytesOfPayloadRemaining > 0) { + size_t sizeAvailableForPayload = 188 - 4; + + size_t numBytesOfPayload = numBytesOfPayloadRemaining; + + if (numBytesOfPayload > sizeAvailableForPayload) { + numBytesOfPayload = sizeAvailableForPayload; + + if (alignPayload && numBytesOfPayload > 16) { + numBytesOfPayload -= (numBytesOfPayload % 16); + } + } + + size_t numPaddingBytes = sizeAvailableForPayload - numBytesOfPayload; + ALOGI("packet %zd contains %zd padding bytes and %zd bytes of payload", + numTSPackets + 1, numPaddingBytes, numBytesOfPayload); + + numBytesOfPayloadRemaining -= numBytesOfPayload; + ++numTSPackets; + } +#else + // This is how many bytes of payload each subsequent TS packet + // can contain at most. + sizeAvailableForPayload = 188 - 4; + size_t sizeAvailableForAlignedPayload = sizeAvailableForPayload; + if (alignPayload) { + // We're only going to use a subset of the available space + // since we need to make each fragment a multiple of 16 in size. + sizeAvailableForAlignedPayload -= + (sizeAvailableForAlignedPayload % 16); + } + + size_t numFullTSPackets = + numBytesOfPayloadRemaining / sizeAvailableForAlignedPayload; + + numTSPackets += numFullTSPackets; + + numBytesOfPayloadRemaining -= + numFullTSPackets * sizeAvailableForAlignedPayload; + + // numBytesOfPayloadRemaining < sizeAvailableForAlignedPayload + if (numFullTSPackets == 0 && numBytesOfPayloadRemaining > 0) { + // There wasn't enough payload left to form a full aligned payload, + // the last packet doesn't have to be aligned. + ++numTSPackets; + } else if (numFullTSPackets > 0 + && numBytesOfPayloadRemaining + + sizeAvailableForAlignedPayload > sizeAvailableForPayload) { + // The last packet emitted had a full aligned payload and together + // with the bytes remaining does exceed the unaligned payload + // size, so we need another packet. + ++numTSPackets; + } +#endif } if (flags & EMIT_PAT_AND_PMT) { @@ -755,8 +860,6 @@ status_t TSPacketizer::packetize( uint64_t PTS = (timeUs * 9ll) / 100ll; - bool padding = (PES_packet_length < (188 - 10)); - if (PES_packet_length >= 65536) { // This really should only happen for video. CHECK(track->isVideo()); @@ -765,19 +868,37 @@ status_t TSPacketizer::packetize( PES_packet_length = 0; } + size_t sizeAvailableForPayload = 188 - 4 - 14 - numStuffingBytes; + if (PES_private_data_len > 0) { + sizeAvailableForPayload -= PES_private_data_len + 1; + } + + size_t copy = accessUnit->size(); + + if (copy > sizeAvailableForPayload) { + copy = sizeAvailableForPayload; + + if (alignPayload && copy > 16) { + copy -= (copy % 16); + } + } + + size_t numPaddingBytes = sizeAvailableForPayload - copy; + uint8_t *ptr = packetDataStart; *ptr++ = 0x47; *ptr++ = 0x40 | (track->PID() >> 8); *ptr++ = track->PID() & 0xff; - *ptr++ = (padding ? 0x30 : 0x10) | track->incrementContinuityCounter(); - if (padding) { - size_t paddingSize = 188 - 10 - PES_packet_length; - *ptr++ = paddingSize - 1; - if (paddingSize >= 2) { + *ptr++ = (numPaddingBytes > 0 ? 0x30 : 0x10) + | track->incrementContinuityCounter(); + + if (numPaddingBytes > 0) { + *ptr++ = numPaddingBytes - 1; + if (numPaddingBytes >= 2) { *ptr++ = 0x00; - memset(ptr, 0xff, paddingSize - 2); - ptr += paddingSize - 2; + memset(ptr, 0xff, numPaddingBytes - 2); + ptr += numPaddingBytes - 2; } } @@ -813,25 +934,14 @@ status_t TSPacketizer::packetize( *ptr++ = 0xff; } - // 18 bytes of TS/PES header leave 188 - 18 = 170 bytes for the payload - - size_t sizeLeft = packetDataStart + 188 - ptr; - size_t copy = accessUnit->size(); - if (copy > sizeLeft) { - copy = sizeLeft; - } - memcpy(ptr, accessUnit->data(), copy); ptr += copy; - CHECK_EQ(sizeLeft, copy); - memset(ptr, 0xff, sizeLeft - copy); + CHECK_EQ(ptr, packetDataStart + 188); packetDataStart += 188; size_t offset = copy; while (offset < accessUnit->size()) { - bool padding = (accessUnit->size() - offset) < (188 - 4); - // for subsequent fragments of "buffer": // 0x47 // transport_error_indicator = b0 @@ -843,35 +953,40 @@ status_t TSPacketizer::packetize( // continuity_counter = b???? // the fragment of "buffer" follows. + size_t sizeAvailableForPayload = 188 - 4; + + size_t copy = accessUnit->size() - offset; + + if (copy > sizeAvailableForPayload) { + copy = sizeAvailableForPayload; + + if (alignPayload && copy > 16) { + copy -= (copy % 16); + } + } + + size_t numPaddingBytes = sizeAvailableForPayload - copy; + uint8_t *ptr = packetDataStart; *ptr++ = 0x47; *ptr++ = 0x00 | (track->PID() >> 8); *ptr++ = track->PID() & 0xff; - *ptr++ = (padding ? 0x30 : 0x10) | track->incrementContinuityCounter(); + *ptr++ = (numPaddingBytes > 0 ? 0x30 : 0x10) + | track->incrementContinuityCounter(); - if (padding) { - size_t paddingSize = 188 - 4 - (accessUnit->size() - offset); - *ptr++ = paddingSize - 1; - if (paddingSize >= 2) { + if (numPaddingBytes > 0) { + *ptr++ = numPaddingBytes - 1; + if (numPaddingBytes >= 2) { *ptr++ = 0x00; - memset(ptr, 0xff, paddingSize - 2); - ptr += paddingSize - 2; + memset(ptr, 0xff, numPaddingBytes - 2); + ptr += numPaddingBytes - 2; } } - // 4 bytes of TS header leave 188 - 4 = 184 bytes for the payload - - size_t sizeLeft = packetDataStart + 188 - ptr; - size_t copy = accessUnit->size() - offset; - if (copy > sizeLeft) { - copy = sizeLeft; - } - memcpy(ptr, accessUnit->data() + offset, copy); ptr += copy; - CHECK_EQ(sizeLeft, copy); - memset(ptr, 0xff, sizeLeft - copy); + CHECK_EQ(ptr, packetDataStart + 188); offset += copy; packetDataStart += 188; |