mirror of
https://github.com/qrtc/ffmpeg-dev-go.git
synced 2025-10-05 15:47:33 +08:00
2023-10-31 09:16:44 CST W44D2
This commit is contained in:
aggresss
260
examples/decode-filter-audio/main.go
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260
examples/decode-filter-audio/main.go
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@@ -0,0 +1,260 @@
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package main
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import (
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"fmt"
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"os"
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"syscall"
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"unsafe"
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ffmpeg "github.com/qrtc/ffmpeg-dev-go"
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)
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var (
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filterDescr = "aresample=8000,aformat=sample_fmts=s16:channel_layouts=mono"
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player = "ffplay -f s16le -ar 8000 -ac 1 -"
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audioStreamIndex int32 = -1
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)
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func openInputFile(filename string) (decCtx *ffmpeg.AVCodecContext, fmtCtx *ffmpeg.AVFormatContext, ret int32) {
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var (
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dec *ffmpeg.AVCodec
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)
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if ret = ffmpeg.AvFormatOpenInput(&fmtCtx, filename, nil, nil); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot open input file\n")
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return nil, nil, ret
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}
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if ret = ffmpeg.AvFormatFindStreamInfo(fmtCtx, nil); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot find stream information\n")
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return nil, nil, ret
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}
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// select the audio stream
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if ret = ffmpeg.AvFindBestStream(fmtCtx, ffmpeg.AVMEDIA_TYPE_AUDIO, -1, -1, &dec, 0); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot find an audio stream in the input file\n")
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return nil, nil, ret
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}
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audioStreamIndex = ret
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// create decoding context
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if decCtx = ffmpeg.AvCodecAllocContext3(dec); decCtx == nil {
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return nil, nil, ffmpeg.AVERROR(syscall.ENOMEM)
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}
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ffmpeg.AvCodecParametersToContext(decCtx, fmtCtx.GetStreams()[audioStreamIndex].GetCodecpar())
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// init the audio decoder
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if ret = ffmpeg.AvCodecOpen2(decCtx, dec, nil); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot open audio decoder\n")
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return nil, nil, ret
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}
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return decCtx, fmtCtx, 0
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}
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func initFilters(decCtx *ffmpeg.AVCodecContext, fmtCtx *ffmpeg.AVFormatContext, filtersDescr string) (
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filterGraph *ffmpeg.AVFilterGraph, buffersinkCtx, buffersrcCtx *ffmpeg.AVFilterContext, ret int32) {
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var (
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abuffersrc = ffmpeg.AvFilterGetByName("abuffer")
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abuffersink = ffmpeg.AvFilterGetByName("abuffersink")
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outputs = ffmpeg.AvFilterInoutAlloc()
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inputs = ffmpeg.AvFilterInoutAlloc()
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outSampleFmts = []ffmpeg.AVSampleFormat{ffmpeg.AV_SAMPLE_FMT_S16, -1}
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outChannelLayouts = []int64{int64(ffmpeg.AV_CH_LAYOUT_MONO), -1}
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outSampleRates = []int32{8000, -1}
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timeBase = fmtCtx.GetStreams()[audioStreamIndex].GetTimeBase()
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args string
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outlink *ffmpeg.AVFilterLink
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)
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filterGraph = ffmpeg.AvFilterGraphAlloc()
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if outputs == nil || inputs == nil || filterGraph == nil {
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ret = ffmpeg.AVERROR(syscall.ENOMEM)
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goto end
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}
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// buffer audio source: the decoded frames from the decoder will be inserted here.
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if decCtx.GetChLayoutAddr().GetOrder() == ffmpeg.AV_CHANNEL_ORDER_UNSPEC {
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ffmpeg.AvChannelLayoutDefault(decCtx.GetChLayoutAddr(), decCtx.GetChLayoutAddr().GetNbChannels())
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}
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args = fmt.Sprintf("time_base=%d/%d:sample_rate=%d:sample_fmt=%s:channel_layout=0x%d",
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timeBase.GetNum(), timeBase.GetDen(), decCtx.GetSampleRate(),
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ffmpeg.AvGetSampleFmtName(decCtx.GetSampleFmt()), decCtx.GetChLayoutAddr().GetNbChannels())
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_INFO, "audio source args: %s\n", args)
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if ret = ffmpeg.AvFilterGraphCreateFilter(&buffersrcCtx, abuffersrc, "in",
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args, nil, filterGraph); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot create audio buffer source\n")
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goto end
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}
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// buffer audio sink: to terminate the filter chain.
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if ret = ffmpeg.AvFilterGraphCreateFilter(&buffersinkCtx, abuffersink, "out",
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ffmpeg.NIL, nil, filterGraph); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot create audio buffer sink\n")
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goto end
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}
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if ret = ffmpeg.AvOptSetIntList(buffersinkCtx, "sample_fmts", &outSampleFmts[0], -1,
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ffmpeg.AV_OPT_SEARCH_CHILDREN); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot set output sample format\n")
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goto end
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}
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if ret = ffmpeg.AvOptSetIntList(buffersinkCtx, "channel_layouts", &outChannelLayouts[0], -1,
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ffmpeg.AV_OPT_SEARCH_CHILDREN); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot set output channel layout\n")
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goto end
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}
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if ret = ffmpeg.AvOptSetIntList(buffersinkCtx, "sample_rates", &outSampleRates[0], -1,
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ffmpeg.AV_OPT_SEARCH_CHILDREN); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot set output sample rate\n")
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goto end
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}
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// Set the endpoints for the filter graph. The filter_graph will
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// be linked to the graph described by filters_descr.
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// The buffer source output must be connected to the input pad of
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// the first filter described by filters_descr; since the first
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// filter input label is not specified, it is set to "in" by
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// default.
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outputs.SetName("in")
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outputs.SetFilterCtx(buffersrcCtx)
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outputs.SetPadIdx(0)
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outputs.SetNext(nil)
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// The buffer sink input must be connected to the output pad of
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// the last filter described by filters_descr; since the last
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// filter output label is not specified, it is set to "out" by
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// default.
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inputs.SetName("out")
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inputs.SetFilterCtx(buffersinkCtx)
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inputs.SetPadIdx(0)
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inputs.SetNext(nil)
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if ret = ffmpeg.AvFilterGraphParsePtr(filterGraph, filtersDescr, &inputs, &outputs, nil); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot parse filter graph\n")
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goto end
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}
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if ret = ffmpeg.AvFilterGraphConfig(filterGraph, nil); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Cannot config filter graph\n")
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goto end
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}
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// Print summary of the sink buffer
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// Note: args buffer is reused to store channel layout string
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outlink = buffersinkCtx.GetInputs()[0]
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args = ffmpeg.AvChannelLayoutDescribe(outlink.GetChLayoutAddr())
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_INFO, "Output: srate:%dHz fmt:%s chlayout:%s\n",
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outlink.GetSampleRate(),
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ffmpeg.AvStringIfNull(ffmpeg.AvGetSampleFmtName(outlink.GetFormat()), "?"),
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args)
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end:
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ffmpeg.AvFilterInoutFree(&inputs)
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ffmpeg.AvFilterInoutFree(&outputs)
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return filterGraph, buffersinkCtx, buffersrcCtx, ret
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}
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func printFrame(frame *ffmpeg.AVFrame) {
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n := frame.GetNbSamples() * frame.GetChLayoutAddr().GetNbChannels()
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p := (*uint16)(unsafe.Pointer(frame.GetData()[0]))
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data := unsafe.Slice(p, n)
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for i := int32(0); i < n; i++ {
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os.Stdout.Write([]byte{byte(data[i] & 0xFF), byte(data[i] >> 8 & 0xFF)})
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}
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}
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func main() {
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var (
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packet ffmpeg.AVPacket
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ret int32
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decCtx *ffmpeg.AVCodecContext
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fmtCtx *ffmpeg.AVFormatContext
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filterGraph *ffmpeg.AVFilterGraph
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buffersinkCtx *ffmpeg.AVFilterContext
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buffersrcCtx *ffmpeg.AVFilterContext
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)
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frame := ffmpeg.AvFrameAlloc()
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filtFrame := ffmpeg.AvFrameAlloc()
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if frame == nil || filtFrame == nil {
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fmt.Fprintf(os.Stderr, "Could not allocate frame")
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os.Exit(1)
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}
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if len(os.Args) != 2 {
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fmt.Fprintf(os.Stderr, "Usage: %s file | %s\n", os.Args[0], player)
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os.Exit(1)
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}
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if decCtx, fmtCtx, ret = openInputFile(os.Args[1]); ret < 0 {
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goto end
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}
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if filterGraph, buffersinkCtx, buffersrcCtx, ret = initFilters(decCtx, fmtCtx, filterDescr); ret < 0 {
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goto end
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}
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// read all packets
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for {
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if ret = ffmpeg.AvReadFrame(fmtCtx, &packet); ret < 0 {
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break
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}
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if packet.GetStreamIndex() == audioStreamIndex {
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if ret = ffmpeg.AvCodecSendPacket(decCtx, &packet); ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Error while sending a packet to the decoder\n")
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break
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}
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for ret >= 0 {
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ret = ffmpeg.AvCodecReceiveFrame(decCtx, frame)
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if ret == ffmpeg.AVERROR(syscall.EAGAIN) || ret == ffmpeg.AVERROR_EOF {
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break
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} else if ret < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Error while receiving a frame from the decoder\n")
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goto end
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}
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if ret >= 0 {
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// push the audio data from decoded frame into the filtergraph
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if ffmpeg.AvBuffersrcAddFrameFlags(buffersrcCtx, frame, ffmpeg.AV_BUFFERSRC_FLAG_KEEP_REF) < 0 {
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ffmpeg.AvLog(nil, ffmpeg.AV_LOG_ERROR, "Error while feeding the audio filtergraph\n")
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break
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}
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// pull filtered audio from the filtergraph
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for {
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ret = ffmpeg.AvBuffersinkGetFrame(buffersinkCtx, filtFrame)
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if ret == ffmpeg.AVERROR(syscall.EAGAIN) || ret == ffmpeg.AVERROR_EOF {
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break
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}
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if ret < 0 {
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goto end
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}
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printFrame(filtFrame)
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ffmpeg.AvFrameUnref(filtFrame)
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}
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ffmpeg.AvFrameUnref(frame)
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}
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}
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}
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ffmpeg.AvPacketUnref(&packet)
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}
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end:
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ffmpeg.AvFilterGraphFree(&filterGraph)
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ffmpeg.AvCodecFreeContext(&decCtx)
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ffmpeg.AvFormatCloseInput(&fmtCtx)
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ffmpeg.AvFrameFree(&frame)
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ffmpeg.AvFrameFree(&filtFrame)
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if ret < 0 && ret != ffmpeg.AVERROR_EOF {
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fmt.Fprintf(os.Stderr, "Error occurred: %s\n", ffmpeg.AvErr2str(ret))
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os.Exit(1)
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}
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os.Exit(0)
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}
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