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#include "FFmpegAudioReader.h"
namespace
{
class AVPacketScope
{
AVPacket* _packet;
public:
explicit AVPacketScope(AVPacket* av_packet)
: _packet(av_packet) {
}
~AVPacketScope() {
av_packet_unref(_packet);
}
};
#if LIBAVCODEC_VERSION_INT < AV_VERSION_INT(57, 24, 100)
// This version doesn't have the new packet alloc API
AVPacket *av_packet_alloc()
{
auto packet = (AVPacket*)av_mallocz(sizeof(AVPacket));
av_packet_unref(packet);
return packet;
}
AVPacket *av_packet_clone(AVPacket *src)
{
auto ret = av_packet_alloc();
av_packet_ref(ret, src);
return ret;
}
void av_packet_free(AVPacket **pkt)
{
av_packet_unref(*pkt);
av_freep(pkt);
}
#endif
} // namespace
namespace sound {
namespace ffmpeg {
FFmpegAudioReader::FFmpegAudioReader(AVFormatContext* av_format_context, AVCodecContext* codec_ctx,
int stream_idx) : _stream_idx(stream_idx),
_format_ctx(av_format_context),
_codec_ctx(codec_ctx) {
}
bool FFmpegAudioReader::readFrame(AVFrame* decode_frame) {
// FFmpeg 3.1 and onwards has a new, better packet handling API but that version is relatively new so we still need
// to support the earlier API. The compatibility code can be removed once the new version is supported by most platforms
#if LIBAVCODEC_VERSION_INT > AV_VERSION_INT(57, 24, 255)
// Process pending frames
auto pending_res = avcodec_receive_frame(_codec_ctx, decode_frame);
if (pending_res == 0) {
// Got a frame
return true;
}
if (pending_res == AVERROR_EOF) {
// No more frames available
return false;
}
if (pending_res != AVERROR(EAGAIN)) {
// Unknown error.
return false;
}
#else
if (_currentPacket != nullptr) {
// Got some data left
int finishedFrame = 0;
auto bytes_read = avcodec_decode_audio4(_codec_ctx, decode_frame, &finishedFrame, _currentPacket);
if (bytes_read < 0) {
// Error!
return false;
}
_currentPacket->data += bytes_read;
_currentPacket->size -= bytes_read;
if (_currentPacket->size <= 0) {
// Done with this packet
av_packet_free(&_currentPacket);
}
if (finishedFrame) {
return true;
}
}
#endif
AVPacket packet;
while (av_read_frame(_format_ctx, &packet) >= 0) {
AVPacketScope packet_scope(&packet);
if (packet.stream_index == _stream_idx) {
#if LIBAVCODEC_VERSION_INT > AV_VERSION_INT(57, 24, 255)
auto res = avcodec_send_packet(_codec_ctx, &packet);
if (res != 0) {
// Error or EOF
return false;
}
res = avcodec_receive_frame(_codec_ctx, decode_frame);
if (res == 0) {
// Got a frame
return true;
}
if (res == AVERROR_EOF) {
// No more frames available
return false;
}
if (res != AVERROR(EAGAIN)) {
// Unknown error.
return false;
}
// EGAIN was returned, send new input
#else
int finishedFrame = 0;
auto bytes_read = avcodec_decode_audio4(_codec_ctx, decode_frame, &finishedFrame, &packet);
if (bytes_read < packet.size) {
// Not all data was read
packet.data += bytes_read;
packet.size -= bytes_read;
_currentPacket = av_packet_clone(&packet);
}
if (finishedFrame) {
return true;
}
if (bytes_read < 0) {
// Error
return false;
}
#endif
}
}
#if LIBAVCODEC_VERSION_INT > AV_VERSION_INT(57, 24, 255)
// Flush decoder
if (avcodec_send_packet(_codec_ctx, nullptr) != 0) {
return false;
}
auto flush_res = avcodec_receive_frame(_codec_ctx, decode_frame);
if (flush_res == 0) {
// Got a frame
return true;
}
#else
AVPacket nullPacket;
memset(&nullPacket, 0, sizeof(nullPacket));
nullPacket.data = nullptr;
nullPacket.size = 0;
int finishedFrame = 1;
auto err = avcodec_decode_audio4(_codec_ctx, decode_frame, &finishedFrame, &nullPacket);
if (finishedFrame && err >= 0) {
return true;
}
#endif
// If we are here then read_frame reached the end or returned an error
return false;
}
FFmpegAudioReader::~FFmpegAudioReader() {
#if LIBAVCODEC_VERSION_INT <= AV_VERSION_INT(57, 24, 255)
if (_currentPacket != nullptr) {
av_packet_unref(_currentPacket);
av_packet_free(&_currentPacket);
}
#endif
}
} // namespace ffmpeg
} // namespace sound
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