| /* |
| * Copyright (c) 2001 Fabrice Bellard |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| * THE SOFTWARE. |
| */ |
| |
| /** |
| * @file |
| * video decoding with libavcodec API example |
| * |
| * @example decode_video.c |
| */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include <libavcodec/avcodec.h> |
| |
| #define INBUF_SIZE 4096 |
| |
| static void pgm_save(unsigned char *buf, int wrap, int xsize, int ysize, |
| char *filename) |
| { |
| FILE *f; |
| int i; |
| |
| f = fopen(filename,"w"); |
| fprintf(f, "P5\n%d %d\n%d\n", xsize, ysize, 255); |
| for (i = 0; i < ysize; i++) |
| fwrite(buf + i * wrap, 1, xsize, f); |
| fclose(f); |
| } |
| |
| static void decode(AVCodecContext *dec_ctx, AVFrame *frame, AVPacket *pkt, |
| const char *filename) |
| { |
| char buf[1024]; |
| int ret; |
| |
| ret = avcodec_send_packet(dec_ctx, pkt); |
| if (ret < 0) { |
| fprintf(stderr, "Error sending a packet for decoding\n"); |
| exit(1); |
| } |
| |
| while (ret >= 0) { |
| ret = avcodec_receive_frame(dec_ctx, frame); |
| if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) |
| return; |
| else if (ret < 0) { |
| fprintf(stderr, "Error during decoding\n"); |
| exit(1); |
| } |
| |
| printf("saving frame %3d\n", dec_ctx->frame_number); |
| fflush(stdout); |
| |
| /* the picture is allocated by the decoder. no need to |
| free it */ |
| snprintf(buf, sizeof(buf), "%s-%d", filename, dec_ctx->frame_number); |
| pgm_save(frame->data[0], frame->linesize[0], |
| frame->width, frame->height, buf); |
| } |
| } |
| |
| int main(int argc, char **argv) |
| { |
| const char *filename, *outfilename; |
| const AVCodec *codec; |
| AVCodecParserContext *parser; |
| AVCodecContext *c= NULL; |
| FILE *f; |
| AVFrame *frame; |
| uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE]; |
| uint8_t *data; |
| size_t data_size; |
| int ret; |
| AVPacket *pkt; |
| |
| if (argc <= 2) { |
| fprintf(stderr, "Usage: %s <input file> <output file>\n", argv[0]); |
| exit(0); |
| } |
| filename = argv[1]; |
| outfilename = argv[2]; |
| |
| pkt = av_packet_alloc(); |
| if (!pkt) |
| exit(1); |
| |
| /* set end of buffer to 0 (this ensures that no overreading happens for damaged MPEG streams) */ |
| memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE); |
| |
| /* find the MPEG-1 video decoder */ |
| codec = avcodec_find_decoder(AV_CODEC_ID_MPEG1VIDEO); |
| if (!codec) { |
| fprintf(stderr, "Codec not found\n"); |
| exit(1); |
| } |
| |
| parser = av_parser_init(codec->id); |
| if (!parser) { |
| fprintf(stderr, "parser not found\n"); |
| exit(1); |
| } |
| |
| c = avcodec_alloc_context3(codec); |
| if (!c) { |
| fprintf(stderr, "Could not allocate video codec context\n"); |
| exit(1); |
| } |
| |
| /* For some codecs, such as msmpeg4 and mpeg4, width and height |
| MUST be initialized there because this information is not |
| available in the bitstream. */ |
| |
| /* open it */ |
| if (avcodec_open2(c, codec, NULL) < 0) { |
| fprintf(stderr, "Could not open codec\n"); |
| exit(1); |
| } |
| |
| f = fopen(filename, "rb"); |
| if (!f) { |
| fprintf(stderr, "Could not open %s\n", filename); |
| exit(1); |
| } |
| |
| frame = av_frame_alloc(); |
| if (!frame) { |
| fprintf(stderr, "Could not allocate video frame\n"); |
| exit(1); |
| } |
| |
| while (!feof(f)) { |
| /* read raw data from the input file */ |
| data_size = fread(inbuf, 1, INBUF_SIZE, f); |
| if (!data_size) |
| break; |
| |
| /* use the parser to split the data into frames */ |
| data = inbuf; |
| while (data_size > 0) { |
| ret = av_parser_parse2(parser, c, &pkt->data, &pkt->size, |
| data, data_size, AV_NOPTS_VALUE, AV_NOPTS_VALUE, 0); |
| if (ret < 0) { |
| fprintf(stderr, "Error while parsing\n"); |
| exit(1); |
| } |
| data += ret; |
| data_size -= ret; |
| |
| if (pkt->size) |
| decode(c, frame, pkt, outfilename); |
| } |
| } |
| |
| /* flush the decoder */ |
| decode(c, frame, NULL, outfilename); |
| |
| fclose(f); |
| |
| av_parser_close(parser); |
| avcodec_free_context(&c); |
| av_frame_free(&frame); |
| av_packet_free(&pkt); |
| |
| return 0; |
| } |