It's attached. Guess I never did change the main file yet (I was
writing some of the threads in separate files, but I thought I had
changed the main file as well - guess I didn't yet).
Should do exactly what you want.
Follow the wave header info on the link I provided previously to
figure out what's happening with writing the header, and right at the
end where I go back and fill in the length fields.
Andrew
On Sat, Mar 13, 2010 at 3:54 PM, Yusuke Kenta <[email protected]> wrote:
> Hi Andrew,
>
> Thank you for the reply. Now I understand why I am getting wav files but has
> no information about it. It will be great if you can send some bits of the
> code to help me understand how to write the header.
>
> Regards,
>
> Yusuke Kenta
>
> On Sat, Mar 13, 2010 at 10:11 PM, Andrew Hakman
> <[email protected]>wrote:
>
>> Don't re-encode to "wav", just write out the header yourself, and dump
>> out the samples you get from decode_audio_3.
>> For a good explanation of the header specifics, see
>> https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
>>
>> I had code that did just that a couple weeks ago, but it's in a
>> non-functional state right now as I'm breaking it into multiple
>> threads (and writing wav files wasn't the end goal, just an
>> intermediate step to see that things are working to that point).
>> Haven't had much time to work on that program recently, but I could
>> probably extract some bits of it and send it to you if you thought it
>> would help.
>>
>> Andrew
>>
>> On Sat, Mar 13, 2010 at 9:09 AM, Edward Hau <[email protected]> wrote:
>> > Hi,
>> >
>> > I am using Martin Böhme example from:
>> > http://www.inb.uni-luebeck.de/~boehme/using_libavcodec.html<http://www.inb.uni-luebeck.de/%7Eboehme/using_libavcodec.html>to
>> > open the
>> > video file and read it then implement libavcodec codec to get audio
>> stream.
>> >
>> > I have several attempts so far but no luck and keeping errors due to my
>> lack
>> > of understand how to process and save audio as wav (using defaults from
>> > libavcodec) from video.
>> >
>> > I am using Microsoft Visual studio 2008 and here the coding so far:
>> >
>> > #include <libavcodec\avcodec.h>
>> > #include <libavformat\avformat.h>
>> >
>> > #define INBUF_SIZE 4096
>> >
>> > int main(int argc, char *argv[]) {
>> > FILE *outputFile;
>> > unsigned int i, audioStream;
>> > int frame_size, out_size, enout_size, enoutbuf_size,
>> len;
>> > short *samples;
>> > AVCodecContext *pCodecCtx, *audioEn;
>> > AVCodec *pCodec, *aCodec;
>> > AVFormatContext *pFormatCtx;
>> > CHAR filename[1027];
>> > uint8_t *outbuf, *enoutbuf;
>> > AVPacket packet;
>> >
>> > av_register_all();
>> >
>> > if(av_open_input_file(&pFormatCtx, filename, NULL, 0, NULL)!=0) return
>> -1;
>> > if(av_find_stream_info(pFormatCtx)<0)return -1;
>> > dump_format(pFormatCtx, 0, filename, false);
>> >
>> > //Find audio stream
>> > for(i=0; i < pFormatCtx->nb_streams; i++){
>> > if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_AUDIO)
>> > {
>> > audioStream=i;
>> > break;
>> > }
>> > }
>> >
>> > pCodecCtx=pFormatCtx->streams[audioStream]->codec;
>> >
>> > // Find the decoder for the audio stream
>> > pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
>> > if(pCodec==NULL){
>> > fprintf(stderr, "Cannot find decoder");
>> > return -1; // Codec not found
>> > }
>> >
>> > if(avcodec_open(pCodecCtx,pCodec)<0) return -1;
>> >
>> > outbuf = (uint8_t*)malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
>> >
>> > aCodec=avcodec_find_encoder(CODEC_ID_PCM_S16LE);
>> > if(pCodec==NULL){
>> > fprintf(stderr, "Cannot find decoder");
>> > return -1; // Codec not found
>> > }
>> >
>> > //setting up encoder
>> > audioEn = avcodec_alloc_context();
>> > audioEn->bit_rate = 1411000;
>> > audioEn->sample_rate = 44100;
>> > audioEn->channels = 2;
>> > audioEn->sample_fmt = SAMPLE_FMT_S16;
>> >
>> > if(avcodec_open(audioEn,aCodec)<0){
>> > fprintf(stderr, "Could not open encoder codec");
>> > std::cin.get();
>> > }
>> >
>> > frame_size = audioEn->frame_size;
>> > samples = (short*)malloc(frame_size * 2 * audioEn->channels);
>> > enoutbuf_size = 10000;
>> > enoutbuf = (uint8_t*)malloc(enoutbuf_size);
>> >
>> > outputFile = fopen(".\\temp1.wav", "wb");
>> > if (!outputFile) {
>> > fprintf(stderr, "could not open %s\n", outputFile);
>> > std::cin.get();
>> > exit(1);
>> > }
>> >
>> > while(av_read_frame(pFormatCtx, &packet)>=0){
>> > if(packet.stream_index==audioStream){
>> > for(;;){
>> > if (packet.size == 0)
>> > break;
>> >
>> > while(packet.size >0){
>> > out_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
>> > // Decode audio frame
>> > len = avcodec_decode_audio3(pCodecCtx, (short
>> *)outbuf,
>> > &out_size, &packet);
>> > if (len < 0) {
>> > fprintf(stderr, "Error while decoding\n");
>> > exit(1);
>> > }
>> > if (out_size > 0) {
>> > enout_size=avcodec_encode_audio(audioEn, enoutbuf,
>> > enoutbuf_size, samples);
>> > fwrite(enoutbuf, 1, enout_size, outputFile);
>> > }
>> > packet.size -= len;
>> > packet.data += len;
>> > }
>> > }
>> > av_free_packet(&packet);
>> > }
>> > }
>> > fclose(outputFile);
>> > free(outbuf);
>> >
>> > // Close the codec
>> > avcodec_close(pCodecCtx);
>> >
>> > // Close the video file
>> > av_close_input_file(pFormatCtx);
>> > }
>> >
>> > Regards,
>> >
>> > Yusuke Kenta
>> > _______________________________________________
>> > libav-user mailing list
>> > [email protected]
>> > https://lists.mplayerhq.hu/mailman/listinfo/libav-user
>> >
>> _______________________________________________
>> libav-user mailing list
>> [email protected]
>> https://lists.mplayerhq.hu/mailman/listinfo/libav-user
>>
> _______________________________________________
> libav-user mailing list
> [email protected]
> https://lists.mplayerhq.hu/mailman/listinfo/libav-user
>
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <stdio.h>
int main(int argc, char *argv[]) {
AVFormatContext *pFormatCtx;
int i, videoStream;
int audioStreamCount = 0;
int audioStreams[4];
AVCodecContext *pCodecCtx;
AVCodecContext *aCodecCtx[4];
AVCodec *aCodec[4];
AVCodec *pCodec;
AVFrame *pFrame;
AVFrame *pFrameRGB;
AVPacket packet;
int frameFinished;
int numBytes;
uint8_t *buffer;
int wave_tot_byte_count=0;
int16_t *decode_buffer;
int packet_counter=0, frame_counter=0;
char *wavebuffer;
int ok;
ok=posix_memalign(&wavebuffer, 16, 256);
if (ok!=0)
{
printf("error, could not allocate wave output buffer\n");
return -1;
}
ok=posix_memalign(&decode_buffer, 16, AVCODEC_MAX_AUDIO_FRAME_SIZE*5);
if (ok!=0)
{
printf("error, could not allocate decode buffer\n");
return -1;
}
FILE *waveFile;
char waveFilename[32];
// Open output wave file
sprintf(waveFilename, "testout.wave");
waveFile=fopen(waveFilename, "wb");
if(waveFile==NULL)
{
printf("error, cannot open output wave file\n");
return -1;
}
//write wave header
i=0;
sprintf(wavebuffer, "RIFF");
fwrite(wavebuffer,1,4,waveFile);
fwrite(&i,4,1,waveFile);
sprintf(wavebuffer, "WAVEfmt ");
fwrite(wavebuffer,1,8,waveFile);
i=16;
fwrite(&i,4,1,waveFile);
i=1;
fwrite(&i,2,1,waveFile);
i=2; //number of channels
fwrite(&i,2,1,waveFile);
i=48000; //sample rate
fwrite(&i,4,1,waveFile);
i=192000; //byte rate = samplerate * num channels * bits per sample / 8
fwrite(&i,4,1,waveFile);
i=4; //block align - number of bytes for one sample including all channels
fwrite(&i,2,1,waveFile);
i=16; //bits per sample
fwrite(&i,2,1,waveFile);
sprintf(wavebuffer, "data");
fwrite(wavebuffer,1,4,waveFile);
i=0; //data subchunk size - go back and fill this in later
fwrite(&i,4,1,waveFile);
//now ready to write actual samples into wave file
if(argc < 2) {
printf("Please provide a movie file\n");
return -1;
}
// Register all formats and codecs
av_register_all();
// Open video file
if(av_open_input_file(&pFormatCtx, argv[1], NULL, 0, NULL)!=0)
return -1; // Couldn't open file
// Retrieve stream information
if(av_find_stream_info(pFormatCtx)<0)
return -1; // Couldn't find stream information
// Dump information about file onto standard error
// dump_format(pFormatCtx, 0, argv[1], 0);
// Find the first video stream
// and up to 4 audio streams
videoStream=-1;
for (i=0; i<4; ++i)
audioStreams[i]=0;
for(i=0; i<pFormatCtx->nb_streams; i++)
{
if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO) {
videoStream=i;
}
if (pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_AUDIO)
{
if (audioStreamCount<4)
{
audioStreams[audioStreamCount]=i;
++audioStreamCount;
}
}
}
printf("found %d audio streams\n", audioStreamCount);
// Get the pointers to the codec context for the audio streams
for (i=0; i<audioStreamCount; ++i)
{
aCodecCtx[i]=pFormatCtx->streams[audioStreams[i]]->codec;
aCodec[i]=avcodec_find_decoder(aCodecCtx[i]->codec_id);
if (aCodec[i]==NULL)
fprintf(stderr, "Unsupported codec in audio stream %d\n",i);
if (avcodec_open(aCodecCtx[i],aCodec[i])<0)
fprintf(stderr, "Can't open codec for audio stream %d\n",i);
}
// Read frames and save first audio stream to wave file
i=0;
while(av_read_frame(pFormatCtx, &packet)>=0)
{
uint8_t *audio_pkt_data = NULL;
int audio_pkt_size = 0;
int pkt_decoded_len = 0;
int frame_decoded_len;
int decode_buff_remain=AVCODEC_MAX_AUDIO_FRAME_SIZE * 5;
// Is this a packet from the video stream?
if(packet.stream_index==videoStream)
{
printf("video packet, pts=%ld, dts=%ld\n",packet.pts, packet.dts);
}
//is this a packet from the first audio stream?
else if(packet.stream_index==audioStreams[0])
{
printf("audio 0 packet, pts=%ld, dts=%ld\n",packet.pts, packet.dts);
//decode the audio packet
frame_decoded_len=decode_buff_remain;
int16_t *decode_buff_ptr = decode_buffer;
int decoded_tot_len=0;
//++packet_counter;
//printf("decoding audio packet %d which is %d bytes\n",packet_counter, audio_pkt_size);
while (audio_pkt_size>0)
{
frame_decoded_len=decode_buff_remain;
//++frame_counter;
pkt_decoded_len = avcodec_decode_audio3(aCodecCtx[0], decode_buff_ptr, &frame_decoded_len, &packet);
//printf("called decode_audio2 %d times now, decoded %d bytes of packet, output is %d bytes\n",frame_counter,pkt_decoded_len,frame_decoded_len);
if (pkt_decoded_len <0) break;
packet.size -= pkt_decoded_len;
packet.data += pkt_decoded_len;
decode_buff_ptr += frame_decoded_len;
decode_buff_remain -= frame_decoded_len;
decoded_tot_len += frame_decoded_len;
}
//write the decode_buffer out to the wave file
fwrite(decode_buffer,1,decoded_tot_len,waveFile);
wave_tot_byte_count+=decoded_tot_len;
}
else if(packet.stream_index==audioStreams[1]) printf("audio 1 packet, pts=%ld, dts=%ld\n",packet.pts, packet.dts);
else if(packet.stream_index==audioStreams[2]) printf("audio 2 packet, pts=%ld, dts=%ld\n",packet.pts, packet.dts);
else if(packet.stream_index==audioStreams[3]) printf("audio 3 packet, pts=%ld, dts=%ld\n",packet.pts, packet.dts);
// Free the packet that was allocated by av_read_frame
av_free_packet(&packet);
}
// Close the video and audio codec
// avcodec_close(pCodecCtx);
for (i=0; i<audioStreamCount; ++i)
{
avcodec_close(aCodecCtx[i]);
}
//go back and fill in the section sizes in the wave file
fseek(waveFile,4,SEEK_SET);
i=wave_tot_byte_count+36;
fwrite(&i,4,1,waveFile);
fseek(waveFile,40,SEEK_SET);
fwrite(&wave_tot_byte_count,4,1,waveFile);
fclose(waveFile);
// Close the video file
av_close_input_file(pFormatCtx);
return 0;
}
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